I

HISTORY OF BOTANY

SACHS

HENRY FROWDE, M.A.

PUBLISHER TO THE UNIVERSITY OF OXFORD LONDON, EDINBURGH NEW YORK AND TORONTO

HISTORY OF BOTANY

(1530— 1860)

BY

JULIUS VON SACHS

PROFESSOR OF BOTANY IN THE UNIVERSITY OF WURZBURG

AUTHORISED TRANSLATION BY

HENRY E. F. GARNSEY, M.A.

Felloxv of Magdalen College^ Oxford REVISED BY

ISAAC BAYLEY BALFOUR, M.A., M.D., F.R.S.

Professor of Botany in the University And Keeper of the Royal Botanic Garden, Edinburgh

SECOND IMPRESSION

OXFORD AT THE CLARENDON PRESS 1906

OXFORD

PRINTED AT THE CLARENDON PRESS

BY HORACE HART, M.A. PRINTER TO THE UNIVERSITY

PREFACE.

Botanical Science is made up of three distinct branches of knowledge, Classification founded on Mor- phology, Phytotomy, and Vegetable Physiology. All these strive towards a common end, a perfect under- standing of the vegetable kingdom, but they differ en- tirely from one another in their methods of research, and therefore presuppose essentially different intellectual en- dowments. That this is the case is abundantly shown by the history of the science, from which we learn that up to quite recent times morphology and classification have developed in almost entire independence of the other two branches. Phytotomy has indeed always maintained a certain connection with physiology, but where principles peculiar to each of them, fundamental questions, had to be dealt with, there they also went their way in almost entire independence of one another. It is only in the present day that a deeper conception of the problems of vegetable life has led to a closer union between the three. I have sought to do justice to this historical fact by treating the parts of my subject separately; but in this case, if the present work was to be kept within suit- able limits, it became necessary to devote a strictly limited space only to each of the three historical delineations. It is obvious that the weightiest and most important matter only could find a place in so narrow a frame, but this I do

vi

Preface.

not exactly regard as a misfortune, and in the interests of the reader it is rather an advantage ; for, in accordance with the objects of the 'General History of the Sciences,' this History of Botany is not intended for professional persons only, but for a wider circle of readers, and to these perhaps even the details presented in it may here and there seem wearisome.

The style of the narrative might have been freer, and greater space might have been allotted to reflections on the inner connection of the whole subject, if I had had before me better preliminary studies in the history of botany ; but as things are, I have found myself especially occupied in ascertaining questions of historical fact, in distinguish- ing true merit from undeserved reputation, in searching out the first beginnings of fruitful thoughts and observing their development, and in more than one case in pro- ducing lengthy refutations of wide-spread errors. These things could not be done within the allotted space without a certain dryness of style and manner, and I have often been obliged to content myself with passing allusions where detailed explanation might have been desired.

As regards the choice of topics, I have given promin- ence to discoveries of facts only when they could be shown to have promoted the development of the science ; on the other hand, I have made it my chief object to dis- cover the first dawning of scientific ideas and to follow them as they developed into comprehensive theories, for in this lies, to my mind, the true history of a science. But the task of the historian of Botany, as thus conceived, is a very difficult one, for it is only with great labour that he succeeds in picking the real thread of scientific thought out of an incredible chaos of empirical material.

Preface.

It has always been the chief hindrance to a more rapid advance in botany, that the majority of writers simply collected facts, or if they attempted to apply them to theoretical purposes, did so very imperfectly. I have therefore singled out those men as the true heroes of our story who not only established new facts, but gave birth to fruitful thoughts and made a speculative use of empirical material. From this point of view I have taken ideas only incidentally thrown out for nothing more than they were originally ; for scientific merit belongs only to the man who clearly recognises the theoretical importance of an idea, and endeavours to make use of it for the pro- motion of his science. For this reason I ascribe little value, for instance, to certain utterances of earlier writers, whom it is the fashion at present to put forward as the first founders of the theory of descent ; for it is an in- dubitable fact that the theory of descent had no scientific value before the appearance of Darwin's book in 1859, and that it was Darwin who gave it that value. Here, as in other cases, it appears to me only true and just to abstain from assigning to earlier writers merits to which prob- ably, if they were alive, they would themselves lay no claim.

J. SACHS.

"WURZBURG,/?^/;/ 2 2, 1875.

THE AUTHOR'S PREFACE

To the English translation of the History of Botany of Juliits von Sachs.

I AM gratefully sensible of the honourable distinction implied in the determination of the Delegates of the Clarendon Press to have my History of Botany trans- lated into the world-wide language of the British Empire. Fourteen years have elapsed since the first appearance of the work in Germany, from fifteen to eighteen years since it was composed, a period of time usually long enough in our age of rapid progress for a scientific work to become obsolete. But if the preparation of an English translation shows that competent judges do not regard the book as obsolete, I should be inclined to refer this to two causes. First of all, no other work of a similar kind has appeared, as far as I know, since 1875, so that mine may still be considered to be, in spite of its age, the latest history of Botany; secondly, it has been my endeavour to ascertain the historical facts by careful and critical study of the older botanical literature in the original works, at the cost indeed of some years of working-power and of consider- able detriment to my health, and facts never lose their value, a truth which England especially has always recognised.

But the present work is not a simple enumeration of the

The Author's Preface. ix

names of botanists and of their writings, no mere list of the dates of botanical discoveries and theories ; such was not at all my plan when I designed it. On the contrary I purposed to present to the reader a picture of the way in which the first beginnings of scientific study of the veget- able world in the sixteenth century made their appearance in alliance with the culture prevailing at the time, and how gradually by the intellectual efforts of gifted men, who at first did not even bear the name of botanists, an ever deepening insight was obtained into the relationship of all plants one to another, into their outer form and inner organisation, and into the vital phenomena or physio- logical processes dependent on these conditions.

For the attainment of this end it was above all things necessary for me to form a clear judgment respecting the influence of the views and principles enunciated by the different authors on the further development of botanical science. This is to the historian of science the central point round which all beside should be disposed, and without which the entire work breaks up into a collection of unmeaning details, and it is one which demands knowledge of the subject, and capacity and impartiality of judgment. On questions connected with times long gone by the decision of the experts has in most cases been already given, though I myself found to my surprise that older authors had for centuries been regarded as the founders of views which they had dis- tinctly repudiated as absurd, showing how necessary it is that the works of our predecessors should from time to time be carefully read and compared together. But in the majority of cases there is no dispute at the present day respecting the historical value, that is the operative

X The Authior's Preface.

influence on posterity, of works written three hundred or even one hundred years ago.

But it is a very different matter when the author of a book like mine ventures, as I have done for sufficient reasons but at the same time with regret, to sit in judg- ment on the works of men of research and experts, who belong to our own time and who exert a lively influence on their generation. In this case the author can no longer appeal to the consentient opinion of his contemporaries ; he finds them divided into parties, and involuntarily be- longs to a party himself. But it is a still more weighty consideration that he may subsequently change his own point of view, and may arrive at a more profound insight into the value of the works which he has criticised ; con- tinued study and maturer years may teach him that he overestimated some things fifteen or twenty years ago and perhaps undervalued others, and facts, once assumed to be well established, may now be acknowledged to be incorrect.

Thus it has happened in my own case also in some but not in many instances, in which I have had to express an opinion respecting the character of works which appeared after i860, and which to some extent influenced my judg- ment on the years immediately preceding them. But this was from fifteen to eighteen years ago when I was working at my History. It might perhaps be expected that I should remove all such expressions of opinion from the work before it is translated. In some few cases, in which this could be effected by simply drawing the pen through a few lines, I have so done ; but it appeared to me that to alter with anxious care every sentence which I should put into a different form at the present day would serve no good

The Author's Preface, xi

purpose, for I came to the conclusion that my book itself may be regarded as a historical fact, and that the kindly and indulgent reader may even be glad to know what one, who has lived wholly in the science and taken an interest in everything in it old and new, thought from fifteen to eighteen years ago of the then reigning theories, repre- senting as he did the view of the majority of his fellow- botanists.

However, these remarks relate only to two famous writers on the subjects with which this History is con- cerned. If the work had been brought to a close with the year 1850 instead of i860, I should hardly have found it necessary to give them so prominent a position in it. Their names are Charles Darwin and Karl Nageli. I would desire that whoever reads what I have written on Charles Darwin in the present work should consider that it contains a large infusion of youthful enthusiasm still remaining from the year 1859, when the 'Origin of Species' delivered us from the unlucky dogma of con- stancy. Darwin's later writings have not inspired me with the like feeling. So it has been with regard to Nageli. He, like Hugo von Mohl, was one of the first among German botanists who introduced into the .study that strict method of thought which had long prevailed in physics, chemistry, and astronomy; but the researches of the last ten or twelve years have unfortunately shown that Nageli's method has been applied to facts which, as facts, were inaccurately observed. Darwin collected innumerable facts from the literature in support of an idea, Nageli applied his strict logic to observations which were in part untrustworthy. The services which each of these men rendered to the science are still

xii

The Author's Preface.

acknowledged ; but my estimate of their importance for its advance would differ materially at the present moment from that contained in my History of Botany. At the same time I rejoice in being able to say that I may some- times have overrated the merits of distinguished men, but have never knowingly underestimated them.

Dr. J. VON SACHS,

Foreign Fellow of the Royal Society.

WuRZBURG, March 34, 1889.

NOTE BY THE TRANSLATOR.

No History of Botany in English has ever been published, and it is to supply in some measure this want, long felt by English-speaking students, that this trans- lation of Professor Sachs' masterl}' sketch has been pre- pared.

H. E. F. G.

CONTENTS.

FIRST BOOK. History of Morphology and Classification

1530-1860.

PAGE

Tntrodnction . . . 3

CHAPTER I.

The Botanists of Germany and the Netherlands from Brnnfels to

Caspar Bauhin, 1530-1623 13

CHAPTER II.

Artificial Systems an'd Terminology of Organs from Cesalpino to

Linnaeus, 1583,-1760 . . ... . . . 37

CHAPTER III.

Development of the Natural System under the Influence of the

Dogma of the Constancy of Species, 1 759-1850 . . . 108

CHAPTER IV.

Morphology under the Influence of the Doctrine of Metamorphosis

and of the Spiral Theory, 1 790-1 850 155

CHAPTER V.

Morphology and Systematic Botany under the Influence of the ' History of Development and the knowledge of the Cryptogams,

1840-1860 182

xiv

Contents.

SECOND BOOK. History of Vegetable Anatomy.

1671-1860.

PAGE

Introduction 219

CHAPTER I.

Phytotomy founded by Malpighi and Grew, 1671-1682 . . . 229

CHAPTER H.

Phytotomy in the Eighteenth Century 246

CHAPTER in.

Examination of the Matured Framework of Cell-Membrane in Plants,

1 800- 1 840 256

CHAPTER IV.

History of Development of the Cell, Formation of Tissues, Molecular

Structure of Organised Forms, 1840-1860 .... 311

THIRD BOOK. History of Vegetable Physiology. 1583-1860.

Introduction 359

CHAPTER I.

History of the Sexual Theory

1. From Aristotle to R. J. Camerarius 376

2. Establishment of the Doctrine of Sexuality in Plants by R. J.

Camerarius, 1691-1694 . 385

3. Dissemination of the New Doctrine ; its Adherents and

Opponents, 1700-1760 390

4. The Theory of Evolution and Epigenesis . . . , 402

Contents.

XV

PAGE

5. Further Development of the Sexual Theory by J. G. Koel-

reuter and Konrad Sprengel, 1761-1793 .... 406

6. New opponents of Sexuality and their refutation by Ex-

periments, 1 785-1 849 422

7. Microscopic Investigation into the Processes of Fertilisation

in the Phanerogams, the Pollen-Tube and Eggs, 1830-1850 431

8. Discovery of Sexuality in the Cryptogams, 1837-1860 . 436

CHAPTER II.

History of the Theory of Nutrition of Plants, 1583-1860 . . 445

1. Cesalpino, 1583 450

2. First Inductive Experiments and Opening of New Points of

View in the History of the Theory of the Nutrition of Plants, to 1730 453

3. Fruitless Attempts to Explain the Movement of the Sap in

Plants, 1 730-1 780 482

4. The Modem Theory of Nutrition Foimded by Ingen-Houss

and Theodore de Saussure, 17 79- 1804 '491

5. Vital Force. Respiration and Heat of Plants. Endosmose,

1 804-1 840 504

6. Settlement of the Question of Food-Material of Plants,

1840-1860 524

CHAPTER III.

History of Phytodynamics

From end of 17th century to about i860 535

Index 565

FIRST BOOK

HISTORY OF MORPHOLOGY AND CLASSIFICATION

(1530-1860)

B

INTRODUCTION.

The authors of the oldest herbals of the i6th century, Brunfels, Fuchs, Bock, Mattioli and others, regarded plants mainly as the vehicles of medicinal virtues ; to them plants were the ingredients in compound medicines, and were there- fore by preference termed 'simplicia,' simple constituents of medicaments. Their chief object was to discover the plants employed by the physicians of antiquity, the knowledge of which had been lost in later times. The corrupt texts of Theophrastus, Dioscorides, Pliny and Galen had been in many respects improved and illustrated by the critical labours of the Italian commentators of the 15th and of the early part of the 1 6th century; but there was one imperfection which no criticism could remove, the highly unsatisfactory descriptions of the old authors or the entire absence of descriptions. It was moreover at first assumed that the plants described by the Greek physicians must grow wild in Germany also, and generally in the rest of Europe ; each author identified a different native plant with some one mentioned by Dioscorides or Theophrastus or others, and thus there arose as early as the 1 6th century a confusion of nomenclature which it was scarcely possible to clear away. As compared with the efforts of the philological commentators, who knew little of plants from their own observation, a great advance was made by the first German composers of herbals, who went straight to nature, described the wild plants growing around them and had figures of them carefully executed in wood. Thus was made the first begin, ning of a really scientific examination of plants, though the aims pursued were not yet truly scientific, for no questions

B 2

4

Introduction.

were proposed as to the nature of plants, their organisation or mutual relations ; the only point of interest was the knowledge of individual forms and of their medicinal virtues.

The descriptions were at first extremely inartistic and un- methodical ; but the effort to make them as exact and clear as was possible led from time to time to perceptions of truth, that came unsought and lay far removed from the object originally in view. It was remarked that many of the plants which Dioscorides had described in his Materia Medica do not grow wild in Germany, France, Spain, and England, and that conversely very many plants grow in these countries, which were evidently unknown to the ancient writers ; it became apparent at the same time that many plants have points of resemblance to one another, which have nothing to do with their medicinal powers or with their importance to agriculture and the arts. In the effort to promote the knowledge of plants for practical purposes by careful description of individual forms, the impression forced itself on the mind of the observer, that there are various natural groups of plants which have a distinct resemblance to one another in form and in other characteristics. It was seen that there were other natural alliances in the veget- able world, beside the three great divisions of trees, shrubs, and herbs adopted by Aristotle and Theophrastus. The first per- ception of natural groups is to be found in Bock, and later herbals show that the natural connection between such plants as occur together in the groups of Fungi, Mosses, Ferns, Coniferae, Umbelliferae, Compositae, Labiatae, Papilionaceae was distinctly felt, though it was by no means clearly understood how this connection was actually expressed ; the fact of natural affinity presented itself unsought as an incidental and indefinite impression, to which no great value was at first attached. The recognition of these groups required no antecedent philosophic reflection or conscious attempt to classify the objects in the vegetable world ; they present themselves to the unprejudiced eye as naturally as do the groups of mammals, birds, reptiles,

Introduction.

5

fishes and worms in the animal kingdom. The real resem- blance of the organisms in such groups is unconsciously accepted by the mind through the association of ideas, and it is not till this involuntary mental act, which in itself requires no effort of the understanding, is accomplished, that any neces- sity is felt for obtaining a clearer idea of the phenomenon, and the sense of this necessity is the first step to intentional sys- tematic enquiry. The series of botanical works published in Germany and the Netherlands from 1530 to 1623, from Brunfels to Kaspar Bauhin, shows very plainly how this per- ception of a grouping by affinity in the vegetable kingdom grew more and more distinct; but it also shows- how these men merely followed an instinctive feeling in the matter, and made no enquiry into the cause of the relationship which they perceived.

Nevertheless a great step in advance was thus taken ; all the foreign matter introduced into the description of plants by medical superstition and practical considerations was seen to be of secondary importance, and was indeed altogether thrown aside by Kaspar Bauhin ; the fact of natural affinity, the vivify- ing principle of all botanical research, came to the front in its place, and awakened the desire to distinguish more exactly whatever was different, and to bring together more carefully all that was like in kind. Thus the idea of natural affinity in plants is not a discovery of any single botanist, but is a product, and to some extent an incidental product, of the practice of describing plants.

But before the exhibition of the natural affinity gave birth to the first efforts at classification on the part of de I'Obel (Lobelius) and afterwards of Kaspar Bauhin, the Italian botanist Cesalpino (1583) had already attempted a system of the vegetable king- dom on a very different plan. He was led to distribute all vegetable forms into definite groups not by the fact of natural affinity, which impressed itself on the minds of the botanists of Germany and the Netherlands through involuntary association

6

Introduction.

of ideas, but by philosophical reflection. Trained in the phi- losophy which flourished in Italy in the i6th century, deeply imbued with the doctrines of Aristotle, and practised in all subtleties of the schools, Cesalpino was not the man to surren- der himself quietly to the influence of nature on the unconscious powers of the mind ; on the contrary, he sought from the first to bring all that he learnt from the writings of others and from his own acute observation of the forms of plants into subjection to his own understanding. Hence he approached the task of the scientific botanist in an entirely different way from that of de I'Obel and Kaspar Bauhin. It was by philosophical reflec- tions on the nature of the plant and on the substantial and accidental value of its parts, according to Aristotelian concep- tions, that he was led to distribute the vegetable kingdom into groups and sub-groups founded on definite marks.

This difference in the origin of the systematic efforts of Cesalpino on the one hand and of de I'Obel and Bauhin on the other is unmistakably apparent ; the Germans were instinc- tively led by the resemblances to the conception of natural groups, Cesalpino on the contrary framed his groups on the sharp distinctions which resulted from the application of pre- determined marks ; all the faults in Bauhin's system are due to incorrect judgment of resemblances, those of Cesalpino to incorrectness in distinguishing.

But the main point of difference lies in the fact, that the system is presented by de I'Obel and Bauhin without any state- ment of the principles on which it rests ; in their account of it the association of ideas is left to perfect itself in the mind of the reader, as it grew up before in the authors themselves. De rObel and Bauhin are like artists, who convey their own impressions to others not by words and descriptions, but by pictorial representations; Cesalpino, on the other hand, addresses himself at once to the understanding of his reader and shows him on philosophic grounds that there must be a classification, and states the principles of this classifi-

Introduction.

7

cation ; it was on philosophic grounds also that he made the characters of the seed and the fruit the basis of his arrange- ment, while the German botanists, paying little attention to the organs of fructification, were chiefly influenced by the general impression produced by the plant, by its habit as the phrase now is.

The historians of botany have overlooked the real state of the case as here presented, or have not described it with sufficient emphasis ; due attention has not been paid to the fact, that systematic botany,' as it began to develope in the 17th century, contained within itself from the first two oppos- ing elements ; on the one hand the fact of a natural affinity indistinctly felt, which was brought out by the botanists of Germany and the Netherlands, and on the other the desire, to which Cesalpino first gave expression, of arriving by the path of clear perception at a classification of the vegetable kingdom which should satisfy the understanding. These two elements of systematic investigation were entirely incommensurable ; it was not possible by the use of arbitrary principles of classification which satisfied the understanding to do justice at the same time to the instinctive feeling for natural affinity which would not be argued away. This incommensurability between natural affinity and a priori grounds of classification is everywhere expressed in the systems embracing the whole vegetable kingdom, which were proposed up to 1736, and which including those of Cesalpino and Linnaeus were not less in number than fifteen. It is the custom to describe these systems, of which those of Cesalpino, Morison, Ray, Bachmanh (Rivinus), and Tournefort are the most important, by the on^ word 'artificial'^; but it was by no means the intention of those men to propose classifications of the vegetable kingdom which should be merely artificial, and do no more than off"er an

^ It will be shown in a later chapter that Linnaeus' sexual system was intended to be artificial.

8

Introduction,

arrangement adnpted for ready reference. It is true that the botanists of the 17th century and Linnaeus himself often spoke of faciHty of use as a great object to be kept in view in con- structing a system ; but every one who brought out a new system did so really because he believed that his own was a better expression of natural affinities than those of his pre- decessors. If some like Ray and Morison were more influenced by the wish to exhibit natural affinities by means of a system, and others as Tournefort and Magnol thought more of framing a perspicuous and handy arrangement of plants, yet it is plain from the objections which every succeeding systematist makes to his predecessors, that the exhibition of natural affinities was more or less clearly in the minds of all as the main object of the system ; only they all employed the same wrong means for securing this end, for they fancied that natural affinities could be brought out by the use of a few easily recognised marks, whose value for systematic purposes had been arbitrarily de- termined. This opposition between means and end runs through all systematic botany from Cesalpino in 1583 to Linnaeus in 1736.

But a new departure dates from Linnaeus himself, since he was the first who clearly perceived the existence of this discord. He was the first who said distinctly, that there is a natural system of plants, which could not be established by the use of predetermined marks, as had been previously attempted, and that even the rules for framing it were still undiscovered. In his Fragments of the date of 1738, he gave a list of sixty-five groups or orders, which he regarded provisionally as cycles of natural affinity, but he did not venture to give their character- istic marks. These groups, though better separated and more naturally arranged than those of Kaspar Bauhin, were like his founded solely on a refined feeling for the relative resemblances and graduated differences that were observed in comparing plants with one another, and this is no less true of the enumer- ation of natural families attempted by Bernard de Jussieu in

Introduction.

9

1759. To such of these small groups of related forms as had not been already named both Linnaeus and -Jussieu gave names, which they took not from certain marks, but from the name of a genus in each group. But this mode of naming plainly expresses the idea which from that time forward prevailed in systematic botany, that there is a common type lying at the foundation of each natural group, from which all its forms though specifically distinct can be derived, as the forms of a crystal may all be derived from one fundamental form, an idea which was also expressed by Pyrame de Candolle in 18 19.

But botanists could not rest content with merely naming natural groups ; it was necessary to translate the indistinct feeling, which had suggested the groups of Linnaeus and Bernard de Jussieu, into the language of science by assigning clearly recognised marks ; and this was from this time forward the task of systematists from Antoine Laurent de Jussieu and de Candolle to Endlicher and Lindley. But it cannot be denied, that later systematists repeatedly committed the fault of splitting up natural groups of affinity by artificial divisions and of bringing together the unlike, as Cesalpino and the botanists of the 17th century had done before them, though continued practice was always leading to a more perfect exhibition of natural affinities.

But while natural relationship was thus becoming more and more the guiding idea in the minds of systematists, and the experience of centuries was enforcing the lesson, that prede- termined grounds of classification could not do justice to natural affinities, the fact of affinity became itself more unintelligible and mysterious. It seemed impossible to give a clear and precise definition of the conception, the exhibition of which was felt to be the proper object of all efforts to discover the natural system, and which continued to be known by the name of affinity. A sense of this mystery is expressed in the sentence of Linnaeus : ' It is not the character (the marks used to characterise the genus) which makes the genus, but the genus

lO

Introduction.

which makes the character;' but the very man, who first distinctly recognised this difficulty in the natural system, helped to increase it by his doctrine of the constancy of species. This doctrine appears in Linnaeus in an unobtrusive form, rather as resulting from daily experience and liable to be modified by further investigation ; but it became with his Successors an article of faith, a dogma, which no botanist could even doubt without losing his scientific reputation ; and thus during more than a hundred years the belief, that every organic form owes its existence to a separate act of creation and is therefore absolutely distinct from all other forms, subsisted side by side with the fact of experience, that there is an intimate tie of relationship between these forms, which can only be imperfectly indicated by definite marks. Every systematist knew that this relationship was something more than mere resemblance perceivable by the senses, while thinking men saw the contradiction between the assumption of an absolute difference of origin in species (for that is what is meant by their constancy) and the fact of their affinity. Linnaeus in his later years made some strange attempts to explain away this contradiction ; his successors adopted a way of their own ; various scholastic notions from the 1 6th century still survived among the systematists, especially after Linnaeus had assumed the lead among them, and it was thought that the dogma of the constancy of species might find especially in Plato's misinterpreted doctrine of ideas a philosophical justifi- cation, which was the more acceptable because it harmonised well with the tenets of the Church. If, as Elias Fries said in 1835, there is ' quoddam supranaturale' in the natural system, namely the affinity of organisms, so much the better for the system ; in the opinion of the same writer each division of the system expresses an idea ('singula sphaera (sectio) ideam quandam exponit '), and all these ideas might easily be explained in their ideal connection as representing the plan of creation. If observation and theoretical considerations occasionally

Introduction, 1 1

suggested objections to such views, these objections were usually little regarded, and in fact reflections of this kind on the real meaning of the natural system did not often make their appearance ; the most intelligent men turned away with an uncomfortable feeling from these doubts and difficulties, and preferred to devote their time and powers to the discovery of affinities in individual forms. At the same time it was well understood that the question was one which lay at the foundation of the science. At a later period the researches of Nageli and others in mor- phology resulted in discoveries of the greatest importance to systematic botany, and disclosed facts which were necessarily fatal to the hypothesis, that every group in the system represents an idea in the Platonic sense ; such for instance were the re- markable embryological relations, which Hofmeister discovered in 1 85 1, between Angiosperms, Gymnosperms, Vascular Crypto- gams and Muscineae ; nor was it easy to reconcile the fact, that the physiologico-biological peculiarities on the one hand and the morphological and systematic characters on the other are commonly quite independent of one another, with the plan of creation as conceived by the systematists. Thus an oppo- sition between true scientific research and the theoretical views of the systematists became more and more apparent, and no one who paid attention to both could avoid a painful feeling of uncertainty with respect to this portion of the science. This feeling was due to the dogma of the constancy of species, and to the consequent impossibility of giving a scientific definition of the idea of affinity.

This state of things finally ceased with the appearance of Darwin's first and best book on the origin of species in 1859 ; from a multitude of facts, some new, but most of them long well-known, he showed that the constancy of species was no longer an open question; that the doctrine was no result of exact observation, but an article of faith opposed to observa- tion. The establishment of this truth was followed almost as a

12

Introduction,

matter of course by the true conception of that which had been hitherto figuratively called affinity ; the degrees of affinity ex- pressed in the natural system indicated the different degrees of derivation of the varying progeny of common parents ; out of affinity taken in a figurative sense arose a real blood-relation- ship, and the natural system became a table of the pedigree of the vegetable kingdom. Here was the solution of the ancient problem.

Darwin's theory has this special interest in the history of the science, that it established clearness in the place of obscurity, a scientific principle in place of a scholastic mode of thought, in the domain of systematic botany and morphology. Yet Darwin did not effect this change in opposition to the historical development of our science or independently of it ; on the contrary his great merit is that he has correctly appreciated the problems long existing in systematic botany and morphology from the point of view of modern research, and has solved them.

That the constancy of species is incompatible with the idea of affinity, that the morphological (genetic) nature of organs does not proceed on parallel lines with their physiological and functional significance, are facts which were known in botany and zoology before the time of Darwin ; but he was the first to show, that variation and natural selection in the struggle for existence solve these problems, and enable us to conceive of these facts as the necessary effects of known causes ; it is at the same time explained, why the natural affinity first recog- nised by de I'Obel and Kaspar Bauhin cannot be exhibited by the use of predetermined principles of classification, as was attempted by Cesalpino.

CHAPTER I.

The Botanists of Germany and the Netherlands from

BrUNFELS to KaSPAR BAUHIN^

1530-1623.

When those who are accustomed to modem botanical litera- ture take up for the first time the works of Otto Brunfels (1530), Leonard Fuchs (1542), Hieronymus Bock (Tragus), or of the later authors Rembert Dodoens (Dodonaus), Charles de I'Ecluse (Carolus Clusius), Matthias de I'Obel (Lobelius, 1576), or even those of Kaspar Bauhin from the beginning of the 17th century, they are surprised not only by the strange form, the curious and unfamiliar accessories from which what is really useful must be laboriously extracted, but still more by the extraordinary poverty of thought which characterises these composers of usually very thick folios. If however instead of travelling backwards from the present time they pursue the opposite direction ; if they have previously occupied themselves with the botanical views of Aristotle and the comprehensive botanical works of his disciple Theophrastus of Eresus, with Pliny's Natural History and the medical science of Dioscorides ;

' Kurt Sprengel in his 'Geschichte der Botanik,' i. 1817, and Ernst Meyer in his ' Geschichte der Botanik,' iv. 1857 have described the connection between the first beginnings of modern botany and the general state of learning in the 15th and i6th centuries; a particularly interesting notice of Valerius Cordus from the pen of Thilo Irmisch will be found in the ' Prii- fungsprogramm ' of the Schwarzburg gymnasium of Sondershausen for 1862. Here, as throughout, the present work will be confined to the investigation and description of the development of strictly botanical ideas.

14 Botanists of Germany and the Netherlands [Book i.

if they have made themselves acquainted with the botanical literature of the middle ages and noted how it continually grows less and less valuable, and have proceeded through the works of Albertus Magnus, as prolix as they are deficient in ideas, to the * Hortus Sanitatis ' (Garden of Health), the popu- lar work on natural history before and after 1500, and similar productions, then certainly they receive a very different and almost imposing impression even from the first herbals, those of Brunfels, Bock, and Fuchs. These books will appear to them almost modern in comparison with the last-named pro- ductions of medieval superstition, nor will they fail to perceive that a new epoch of natural science commenced with these men, and above all that they laid the foundations of modern botany. They give us, it is true, nothing but separate descrip- tions of the wild and cultivated plants of Germany, and these for the most part of common occurrence, arranged by Fuchs alphabetically, by Bock grouped under the heads of herbs, shrubs, and trees, and following one another under each head in the most motley order ; it is true that these descriptions are so naive and inartistic as hardly to offer points of comparison with modern scientifically correct diagnoses ; but the great point is, that they are taken from the plants as they lay before the writers, who had often seen and carefully examined them. Woodcuts are added to supply any defects in the description, and to give a clear idea of the plant intended by the name ; and these figures, which always give the whole .plant and were drawn immediately from nature by the hands of practised artists, are so true to nature that a botanist's eye at once recognises in every case the object meant to be repre- sented. These figures and descriptions (the latter are wanting in Brunfels \ 1530) would have rendered a great service to the

^ Otto Brunfels, born at Mainz before the year 1500, was at first a student .of theology and a monk ; becoming a convert to Protestantism he was actively engaged at Strassburg first as a teacher and afterwards as a physician; he died in 1534.

Chap. I.] from Bruftfels to Kaspar Bauhih j 5

science, even if they had not been as good as they are ; for botanical literature had sunk so low, that not only were the figures embellished with fabulous additions, as in the ' Hortus Sanitatis,' and sometimes drawn purely from fancy, but the meagre descriptions of quite common plants were not taken from nature, but borrowed from earlier authorities and eked out with superstitious fictions. The powers of independent judgment were oppressed and stunted in the middle ages, till at last the very activity of the senses, resting as it does to a great extent on unconscious operations of the understanding, became weak and sickly ; natural objects presented themselves to the eye even of those who made them their study in grotesquely distorted forms ; every sensuous impression was corrupted and deformed by the influence of a superstitious fancy. In comparison with these perversions the artless descriptions of Bock appear suitable and true, and are refresh- ing from their immediate contact with nature ; while in the more learned Fuchs criticism of other writers is already seen united with actual examination of natural objects. Great was the gain when men began once more to look at plants with open eyes, to take pleasure in their variety and beauty. It was not necessary for a while that they should speculate on the nature of plants, or the cause of plant-life ; time enough for that when sufficient practice had been gained in the percep- tion of their resemblances and differences.

The German fathers of botany connected their labours with the botanical literature of classical antiquity only so far as they sought to recognise in the plants of their own country those named by Theophrastus, Dioscorides, Pliny and Galen. The attempt to do this indeed led to many mistakes, for the descrip- tions of the ancient botanists were very imperfect and often quite unserviceable for the recognition of the plants described. In this point therefore the compilers of herbals found no models worthy of imitation in the old writers. But in seeking to recover a knowledge of the medicinal plants of the Greek

i6 Botanists of Germany and the Netherlands [book i.

physicians \ they were compelled to compare together a great variety of native plants, and thus to exercise and perfect the faculty of apprehending differences of form. This mode of proceeding, arising out of medical requirements, directed the attention entirely to the individual form, which was also the chief thing required in the interest of pure science, and much more was thus gained than if these men had only followed the philosophical writings of Aristotle' and Theophrastus The Greek authors built their views on the philosophy of botany on very weak foundations ; scarcely a plant was known to them exactly in all its parts ; they derived much of their knowledge from the accounts of others, often from dealers in herbs. From this scanty material and from various popular superstitions had Aristotle formed his views on the nature of plants, and if Theophrastus possessed more experimental knowledge, he still saw facts in the light of his master's philosophical doctrines. If we succeed in the present day in extracting much that is accurate from the writings of Aristotle and Theophrastus, it was nevertheless well that the first compilers of herbals ceased to pay attention to them, and occupied themselves with accumu- lating desrciptions of individual plants worked out by them-

^ Beside the herbals mentioned in the text, which may be regarded as scientific works on botany, a considerable number of books