Sept. 7, 1888.] 



SCIENTIFIC NEWS. 



241 



of its form and the part it plays in the plant's economy. That there 

 is here an immense field for investigation there can be no doubt 

 Mr. Darwin himself set us the example in a series of masterly 

 investigations. But the field is well-nigh inexhaustible. The extra- 

 ordinary variety of form which plants exhibit has led to the notion 

 that much of it may have arisen from indifferent variation. No 

 doubt, as Mr. Darwin has pointed out, when one of a group of 

 structures held together by some morphological or physiological 

 nexus varies, the rest will vary correlatively. One variation then 

 may, if advantageous, become adaptive, while the rest will be 

 indifferent. But it appears to me that such a principle should be 

 applied with the greatest caution, and from what I have myself heard 

 fall from Mr. Darwin, I am led to believe that in the Liter years of his 

 life he was disposed to think that every detail of plant structure had 

 some adaptive significance, if only the clue could be found to it. As 

 regards the forms of flowers an enormous body of information has 

 been collected, but the vegetative organs have not yielded their 

 secret to anything like the same extent. My own impression is that 

 they will be found to be adaptive in innumerable ways which at pre- 

 sent are not even suspected. At Kew we have probably a larger 

 number of species assembled together than are to be found any- 

 where on the earth's surface. Here, (hen, is ample material for 

 observation and comparison. But the adaptive significance will 

 doubtless often be found by no means to lie on the surface. Who, 

 for example, could possibly have guessed by inspection the purpose of 

 the glandular bodies on the leaves of Acacia sphcerocephala and on the 

 pulvinus of Cecropia peltata which Belt in the one case and Fritz 

 Miiller in the other have shown to serve as food for ants ? So far 

 from this explanation being far-fetched, Belt found that the former 

 " tree is actually unable to exist without its guard," which it could 

 not secure without some attraction in the shape of food. One fact 

 which strongly impresses me with a belief in the adaptive significance 

 of vegetative characters is the fact that in almost identical forms 

 they are constantly adopted by plants of widely different affinity. If 

 the forms were without significance one would expect them to be 

 infinitely varied. If, however, they are not so, it is intelligible that 

 different plants should independently avail themselves of the same 

 appliances and expedients. 



Although this country is splendidly equipped with appliances for 

 the study of systematic botany, our Universities and colleges fall far 

 behind a standard which would be considered even tolerable on the 

 Continent in the means of studying morphological and physiological 

 botany or of making researches in these subjects. There is not at 

 the moment anywhere in London an adequate botanical laboratory ; 

 and though at most of the Universities matters are not quite so bad, 

 still I am not aware of any one where it is possible to do more 

 than give the routine instruction or to allow the students, when they 

 have passed through this, to work for themselves. It is not easy to 

 see why this should be, because on the animal side the accommoda- 

 tion and appliances for teaching comparative anatomy and physiology 

 are always adequate and often palatial. Still less explicable to me 

 is the tendency on the part of those who have charge of medical 

 education to eliminate botanical study from the medical curriculum, 

 since historically the animal histologists owe everything to botanists. 

 In the seventeenth century Hooke first brought the microscope to 

 the investigation of organic structure, and the tissue he examined 

 was cork. Somewhat later Grew, in his "Anatomy of Plants,'' 

 gave the first germ of the cell theory. During the eighteenth century 

 the anatomists were not merely on a hopelessly wrong tack them- 

 selves, but they were bent on dragging botanists into it also. It was 

 not till 1837, a little more than fifty years ago, that Henle saw that 

 the structure of epithelium was practically the same as that of the 

 Parenchyma plantarum which Grew had described 1 50 years before. 

 Two years later Schwann published his immortal theory, which 

 comprised the ultimate facts of plant and animal anatomy under one 

 view. But it was to a botanist, Von Mohl, that, in 1846, the 

 biological world owed the first clear description of protoplasm, and 

 to another botanist, Cohn (1851), the identification of this with the 

 sarcode of zoologists. 



Now the historic order in discovery is not without its significance. 

 The path which the first investigators found most accessible is doubt- 

 less that which beginners will also find easiest to tread. I do not 

 myself believe that any better access can be obtained to the structure 

 and functions of living tissues than by the study of plants. However, 

 I am not without hopes that the serious study of botany in the 

 laboratory will be in time better cared for. I do not hesitate to 

 claim for it a position of the greatest importance in ordinary scien- 

 tific education. All the essential phenomena of living organisms 

 can be readily demonstrated upon plants. The necessary appliances 

 are not so costly, and the work of the class-room is free from many 

 difficulties with which the student of the animal side of biology has 

 to contend. 



Those, however, who have seriously devoted themselves to the 



pursuit of either morphological or physiological botany need not now 

 be wholly at a loss. The splendid laboratory on Plymouth Sound, 

 the erection of which we owe to the energy and enthusiasm of Pro- 

 fessor Ray Lankester, is open to botanists as well as to zoologists, 

 and affords every opportunity for the investigation of marine plants, 

 in which little of late years has been done in this country. At Kew 

 we owe to private munificence a commodious laboratory, in which 

 much excellent work has already been done. And this Association 

 has made a small grant in aid of the establishment of a laboratory 

 in the Royal Botanic Garden at Peradeniya, in Ceylon. It may be 

 hoped that this will afford facilities for work of the same kind as 

 has yielded Dr. Treub such a rich harvest of results in the Buitenzorg 

 Botanic Garden, in Java. 



Physiological botany, as I have already pointed out, is a field in 

 which this country in the past has accomplished great things. 1 1 

 has not of late, however, obtained an amount of attention in any 

 way proportionate to that devoted to animal physiology. In the 

 interests of physiological science generally this is much to be de- 

 plored ; and I believe that no one was more firmly convinced of 

 this than Mr. Darwin. Only a short time before his death, in 

 writing to Mr. Romanes on a book that he had recently been read- 

 ing, he said that the author had made "a gigantic oversight in 

 never considering plants ; these would simplify the problem for 

 him." This goes to the root of the matter. There is, in my judg- 

 ment, no fundamental biological problem which is not exhibited in 

 a simpler form by plants than animils. It is possible, however, that 

 the_ distaste which seems to exist amongst our biologists for physio- 

 logical botany may be due in some measure to the extremely physical 

 point of view from which it has been customary to treat it on the 

 Continent. It is owing in great measure to the method of Mr. 

 Darwin's own admirable researches that in this country we have 

 been led to a more excellent way. The work which has been lately 

 done in England seems to me full of the highest promise. Mr. 

 Francis Darwin and Mr. Gardiner have each in different directions 

 shown the entirely new point of view which may be obtained by 

 treating plant phenomena as the outcome of the functional activity 

 of protoplasm. I have not the least doubt that by pursuing this 

 path English research will not merely place vegetable physiology, 

 which has hitherto been too much under the influence of Lamarck- 

 ism, on a more rational basis, but that it will also sensibly react, as 

 it has done often before, on animal physiology. 



There is no part of the field of physiological botany which has 

 yielded results of more interest and importance than that which 

 relates to the action of ferments and fermentation ; and I could 

 hardly give you a better illustration of the purely biological method 

 of treating it. I believe that these results, wonderful and fascinat- 

 ing as they are, afford but a faint indication of the range of those 

 that are still to be accomplished. The subject is one of extreme 

 intricacy, and it is not easy to speak about it briefly. To begin 

 with, it embodies two distinct groups of phenomena which have in 

 reality very little which is essential in common. 



What are usually called ferments are perhaps the most remark- 

 able of all chemical bodies, for they have the power of effecting very 

 profound changes in the chemical constitution of other substances, 

 although they may be present in very minute quantity ; but, which 

 is their most singular and characteristic property, they themselves 

 remain unchanged in the process. It may be said without hesita- 

 tion that the whole nutrition of both animals and plants depends on 

 the action of ferments. The organism is incapable of using solid 

 nutrient matter for the repair and extension of its tissues j it must 

 be first brought into a soluble form before it can be made available, 

 and this change is generally brought about by the action of a fer- 

 ment. Animal physiology has long been familiar with the part 

 played by these bodies, and it may be said that no small part of the 

 animal economy is made up of organs required either for the manu- 

 facture of ferments or for the exposure of ingested food to their 

 action. It may seem strange at first sight to speak of analogous 

 processes taking place in plants, but it must be remembered that 

 plant nutrition includes two very distinct stages. Certain parts of 

 plants build up, as every one knows, from external inorganic 

 materials substances which are available for the construction of new 

 tissues. It might be supposed that these are used up as fast as they 

 are formed. But it is not so ; the life of the plant is not a con- 

 tinuous balance of income and expenditure. On the contrary, 

 besides the general maintenance of its structure, the plant has to 

 provide from time to time for enormous resources to meet such ex- 

 hausting demands as the renewal of foliage, the production of 

 flowers, and the subsequent maturing of fruit. 



In such cases the plant has to draw on an accumulated store of 

 solid food, which has rapidly to be converted into the soluble form 

 in which alone it is competent to be drawn off through the tissues 

 to the seat of consumption. And I do not doubt, for my part, that 

 in such cases ferments are brought into play of the same kind and 



