Sept. 13, 1888J 



NATURE 



473 



ketones, &c. {Rerichte, xx. ); Lawson and Collie on the action 

 of heat on salts of tetramethyl-atnmonium (J. Chem. Soc, 

 June 1888) ; Thorpe and Hambly on manganic trioxide (J. 

 Chem. Soc, March 1888) ; besides many others, including 

 papers on analytical processes. To such as these there might 

 subsequently be added the determination of an atomic weight on 

 the model of one of the best masters, as a discipline which could 

 not fail to be impressive, and full of instruction. 



When chemistry is taught, not with professional or technical 

 objects in view, but for the sake of educational effects, as an 

 ingredient in a liberal education, the primary object is to make 

 the pupil observe and think. But with young students it is very 

 important to proceed slowly, for chemistry is really a very 

 difficult subject at first, owing to the variety of strange material s 

 with uncouth names. To reason from particulars to generals is 

 for the unpractised always a difficult process, and in chemistry 

 this is specially the case. With young students it is, in my 

 experience, preferable to adopt a somewhat dogmatic style, 

 which should of course be exchanged for a more cautious one as 

 the pupil proceeds. 



Thus the law of Avogadro can only be given at first as a 

 recognized physical law, without much explanation, since 

 the full apprehension of the evidence upon which it rests 

 can only be secured at a late s-tage of the learner's progress. 

 There is of course great advantage in the use of an inductive 

 method if only it is employed judiciously. Otherwise the result 

 is only confusion. 



A number of papers, pamphlets, and text-books have lately 

 appeared, professing to teach the principles of the science practic- 

 ally and by new methods. Most of these turn out, upon inspec- 

 tion, to be very old methods indeed, but there is a small residue 

 of distinctly original character which are sure to attract, as they 

 deserve, considerable attention. The systems I refer to pro- 

 vide a series of problems which the pupils are called upon to 

 solve. According to this plan the student is not allowed peace- 

 ably to examine the properties of oxygen or sulphur which he 

 now sees for the first time. He must weigh, and measure, and 

 observe, and then infer. All this coming at once upon the head 

 of a beginner seems to me to be well fitted to drive him to 

 despair. 



I well remember the first experiment in chemistry I ever 

 made. It consisted in dissolving zinc in diluted sulphuric acid 

 in an evaporating dish, lighting with a match the bubbles of 

 hydrogen as they rose, and afterwards leaving the solution to 

 crystallize. I was about sixteen, and the bubbles of gas, as well 

 as the crystals I afterwards got, interested me very much. If at 

 that time I had been made to weigh the zinc and acid, and 

 measure the hydrogen with the object of answering some 

 question about the composition of zinc and hydrogen sulphates, 

 I should have been pretty much in the position of a boy ignorant 

 of geometry shut up with the propositions of Euclid and ordered 

 to give the demonstrations. 



I think when we recall such a fact as that Priestley, who 

 discovered oxygen in 1774, failed to the end of his days to under- 

 stand the process of combustion, and actually wrote, in 1800, a 

 pamphlet in defence of "phlogiston," we ought not to be sur- 

 prised when young people, though born a century later, fail to 

 perceive at once the full significance of facts to which they are 

 introduced for the first time. At the outset you cannot reasonably 

 expect a young student both to observe accurately and infer 

 justly. These two things must be kept separate at first, and for 

 this reason among others I believe that attempts to make young 

 students verify for themselves the fundamental propositions of 

 chemistry will not be successful. One has only to trace the origin 

 of one's own convictions in reference to any important fact or 

 principle to perceive that they very seldom spring into existence 

 suddenly, but almost always commence in vagueness and hesita- 

 tion, acquiring consistency and solidity only as the result of 

 accumulated experience. 



I will not pretend to determine what may be included within 

 the wide circle of the functions of the British Association ; but I 

 think I cannot be mistaken in assuming that the advancement of 

 science is dependent in no small degree upon the provision for 

 the efficient teaching of science. I have traced an outline of 

 what has been done in the past, and have endeavoured to show 

 in what respects I think we are deficient at the present time. No 

 matter how ardent may be the aspirations, how earnest the 

 endeavours of the few, progress will be slow unless they are 

 sustained by the sympathy of the many. On one principle the 

 public must surely insist, that only those shall be allowed to 

 teach who know. 



SECTION D. 



BIOLOGY. 



Opening Address by W. T. Thiselton-Dyer, C.M.G., 

 M.A., B.Sc., F.R.S., F.L.S., President of the Section. 



Before we commence the formal business of the Section, I 

 propose to invite your attention to several points which have 

 suggested themselves to me from a consideration of the present 

 position and progress of the study of botany in this country. 



It is not so very long ago that at English Universities, at least, 

 the pursuit of botany was regarded rather as an elegant accom- 

 plishment than as a serious occupation. This is the more remark- 

 able because at every critical point in the history of botanical 

 science the names of our countrymen will be found to occupy an 

 honourable place in the field of progress and discovery. In the 

 seventeenth century, Hooke and Grew laid the foundation of the 

 cell-theory, while Millington, by discovering the function- of 

 stamens, completed the theory of the flower. In the following 

 century, Morison first raised ferns from spores, Lindsay detected 

 the fern prothallus, Ray laid the foundations of a natural classi- 

 fication, Hales discovered root-pressure, and Priestley the 

 absorption of carbon dioxide and the evolution of oxygen by 

 plants. In the early part of the present one we have Knight's 

 discovery of the true cause of geotropism, Daubeny's of the effect 

 upon the processes of plant-life of rays of light of different 

 refrangibility, and, finally, the first description of the cell-nucleus 

 by R. Brown. I need not attempt to carry the list through the 

 last half-century. I have singled out these discoveries as striking 

 landmarks, the starting-points of important developments of the 

 subject. It is enough for my purpose to show that we have 

 always had an important school of botany in England, which has 

 contributed at least its share to the general development of the 

 science. 



I think at the moment, however, we have little cause for 

 anxiety. The academic chairs throughout the three kingdoms 

 are filled, for the most part, with young, enthusiastic, and well- 

 trained men. Botany is everywhere conceded its due position as 

 the twin branch with zoology of biological science. We owe to 

 the enlightened administration of the Oxford University Press 

 the possession of a journal which allows of the prompt and 

 adequate publication of the results of laboratory research. The 

 excellent work which is being done in every part of the botanical 

 field has received the warm sympathy of our colleagues abroad. 

 I need only recall to your recollection, as a striking evidence of 

 this, the remarkable gathering of foreign botanists which will 

 ever make the meeting of this Association at Manchester a 

 memorable event to all of us. The reflection rises sadly to the 

 mind that it can never be repeated. Not many months, as you 

 know, had passed before the two most prominent figures in that 

 happy assemblage had been removed from us by the inexorable 

 hand of death. In Asa Gray we miss a figure which we could 

 never admit belonged wholly to the other side of the Atlantic. 

 In technical botany we recognized him as altogether in harmony 

 with the methods of work and standard of excellence of our own 

 most distinguished taxonomists. But, apart from this, he had 

 that power of grasping large and far-reaching ideas, which, I do 

 not doubt, would have brought him distinction in any branch of 

 science. We owe to him the classical discussion of the facts of 

 plant distribution in the northern hemisphere which is one of 

 the corner-stones of modern geographical botany. He was one 

 of the earliest of distinguished naturalists who gave his adhesion 

 to the theory of Mr. Darwin. A man of simple and sincere 

 piety, the doctrine of descent never presented any difficulty to 

 him. He will remain in our memories as a figure endowed with 

 a sweetness and elevation of character which may be compared 

 even with that of Mr. Darwin himself. 



In De Bary we seem to have suffered no less a personal loss 

 than in the case of Gray. Though, before last year, I do not 

 know that he had ever been in England, so many of our 

 botanists had worked under him that his influence was widely 

 felt amongst us. And it may be said that this was almost equally 

 so in every part of the civilized world. His position as a teacher 

 was in this respect probably unique, and the traditions of his 

 methods of work must permanently affect the progress of botany, 

 and, indeed, have an even wider effect. This is not the occasion 

 to dwell on each of his scientific achievements. It is sufficient 

 to say that we owe to him the foundations of a rational vegetable 

 pathology. He first grasped the true conditions of parasitism hi 

 plants, and not content with working out the complex phases of 

 the life-history of the invading organism, he never lost sight of 



