Sept. 8, 1881] 



NATURE 



443 



occupy, emits no utterance of pleasure or distress. Its life pro- 

 cesses continue so long as material remains, and are regulated 

 mechanically. 



To ui dei-stand this all that is necessary is to extend the con- 

 siderations Avhich have been suggested to us in our very cursory 

 btudy of the nervous mechanism by which the working of the 

 heart and of arteries is governed, to those of locomotion and 

 voice. Both of these we know, on experimental evidence 

 similar to that which enables us to localise the vascular centre, 

 to be regulated by a centre of the same kind. If the be- 

 haviour of the brainless frog is so natural that even the careful 

 and intelligent observer finds it ditihcult to attriliute it to anything 

 less than intelligence, let us ask ourselves whether the chief 

 reason of the difficulty does not lie in thi.o, that the motions in 

 question are habitually performed intelligently and consciously. 

 Regarded as mere mechani-ms, those of locomotion aj-e no doubt 

 more complicated than those of respiration or circulation, but 

 the difference is one of degree, not of kind. And if the 

 respiratory movements are so controlled and regulated by the 

 automatic centre which governs them, that they adapt themselves 

 perfectly to the varying requirements of the organism, there is 

 no reason why we should hesitate in attributing to the centres 

 which preside over locomotion powers which are lomewhat more 

 extended. 



But perhaps the question has alreaiy presented itself to your 

 minds, What does all this come to? Admitting that we are 

 able to prove (i) that in the animal body. Product is always 

 proportional to Process, and (2), as I have endeavoured to show 

 you in the second part of my discourse, that Descartes' dream 

 of animal automatism has been realised, what have we learnt 

 thereby ? Is it true that the work of the last generation is worth 

 more than that of preceding ones ? 



If I only desired to convince you that during the last half- 

 century there has been a greater accession of knowledge about 

 the function of the living organism than dmung the previous 

 one, I might arrange here in a small heap at one end of the 

 table the physiological works of the Hunters, Spallanzani, Fou- 

 tana, Thomas Voung, Benjamin Brodie, Charles Bell, and others, 

 and then proceed to cover the rest of it with the records of 

 original research on physiological subjects since 1831, I should 

 find that, even if I included only genuine work, I should have 

 to heap my table up to the ceiling. But I apprehend this would 

 not give us a true answ er to om' question. Although, etymologi- 

 cally, Science and Knowledge mean the same thing, their real 

 meaning is different. By science we mean, first of all, that 

 knowledge which enables us to sort the things known according 

 to their true relations. On this ground we call Haller the father 

 of physiology, becau-e, reg.irdless of existing theories, he 

 brought together into a system all that was then known by 

 observation or experiment as to the processes of the living body. 

 But in the " Elementa Physiologix- " we have rather that cut of 

 which science springs than science itself. Science can hardly be 

 said to begin until we have by experiment acquired such a 

 knowledge of the relation between events and their antecedents, 

 between processes and their product^, that in our own sphere we 

 are able to forecast the operations of nature, even when they lie 

 beyond the reach of direct observation. I would accordingly 

 claim for physiology a place in the sisterhood of the sciences, 

 not because so large a number of new facts have been brought 

 to light, but because she has in her measure acquired that gift of 

 prevision which has been long enjoyed by ihe higher branches of 

 natural philosophy. In illustration of this I have endeavoured 

 to show you that every step of the laborious investigations under- 

 taken during the last thirty years as to the process of nutrition, 

 has been inspired by the previsions <; f J. R. Mayer, and that what 

 we have learnt with so much labour by experiments on animals is 

 but the realisation of conceptions which existed two hundred 

 years a;;o in the mind of Descartes as to the mechanism of the 

 nervous system. If I wanted another example I might find it 

 in the previsions of Dr. Thomas Young as to the mechanism of 

 the circulation, which for thirty years were utterly disregarded, 

 until, at the epoch to which I have so often adverted, they 

 received their full justification from the experimental investiga- 

 tions of Ludwig. 



But perhaps it will cccur to some one that if physiology founds 

 her claim to be regarded as a science on her power of anticipating 

 the results of her own experiment^, it is unneces'ary to make 

 experiments at all. Although this objection has been frequently 

 heard lately from certain persons who call themselves philo- 

 sophers, it is not very hkely to be made seriously here. The 



answer is, that it is contrary to experier.ce. Although we work 

 in the certainty that evei-y experimental result will come out in 

 accordance with great principles (such as the principle that every 

 plant or animal is both, as regards form and function, the out- 

 come of its past and present conditions, and that in every vital 

 process the same relatiins obtain between expenditure and pro- 

 duct as hold outside of the organism), these principles do little 

 more for us than indicate the direction in which we are to pro- 

 ceed. The history of science teaches us that a general principle 

 is like a ripe seed, which may remain u.sele s and inactive for an 

 indefinite period, until the conditions favoural.ile to its germina- 

 tion come into existence. Thus the conditions for which the 

 theory c:>f animal automatism of Descartes had to wait two 

 centuries, vvere (i) the acquirement of an adequate knowledge of 

 the structure of the animal organism, and (2) the development of 

 the sciences of physics and chemistr)' ; for at no earlier moment 

 were the^e sciences competent to furnish either the knowledge 

 or the meth.jds necessary for its experimental realisation ; and 

 for a reason precisely similar Young's theory of the circulation 

 was disregarded for thirty years. 



I trust that the examples I have placed before you to-day may 

 have been sufficient to show that the investigators who are now 

 working w ith such earnestness in all parts of the world for the 

 advance of physiology, have before them a definite and well- 

 understood pru-pose, that purpose being to acquire an exact 

 knowledge of the chemical and physical proces es of animal 

 life, and of the self-acting machinery by which they are regu- 

 lated for the general good of the organism. The more singly 

 and straightforwardly we direct our efforts to these ends, the 

 sooner we shall attam to the still higher purpo-e — the effectual 

 application of oiur knowledge for the increase of human 

 happiness. 



The Science of Physiology has already afforded her aid to 

 the Art of Medicine in furnishing her with a vast store of 

 knowledge obtained by the experimental investigation of the 

 action of remedies and of the causes of disease. The^e inves- 

 tigations are now being carried on in all parts of the world with 

 great diligence, so that we may confidently anticipate that during 

 the next generation the progress of pathology will be as rapid 

 as that of physiology has been in the past, and that as time goes 

 on the practice of medicine w ill gradually come more and more 

 under the influence of scientific knowledge. That this change 

 is already in progress we have abundant evidence. We need 

 make no effort to hasten the proces';, for we may be quite sure 

 that, as soon as science is competent to dictate, art will be ready 

 to obey. 



SECTION F 



GEOGRAPHY 



Opening Address by Sir Joseph D. Hooker, C.B., 

 K. C.S.I. , F.R.S., &c., President of the Section 



On Geographical Distribution 



It has been suggested that a leading feature of the sectional 

 addresses to be delivered on the occasion of this, the fiftieth 

 anniversary of the meetings of the British Association, should be 

 a leview of the progress made during the last half century in 

 the branches of knowledge which the sections respectively 

 represent. 



It has further been arranged that, at so auspicious an epoch, 

 the sections should, when pos: ibie, be presided over by past 

 Presklents of the Association. This has resulted in almost every 

 sectional chair being occupied by a President eminent as a 

 cuUivator of the science with which his section will be engaged, 

 though not the one I have the honour of filling, which, from the 

 fact of there being no profes ed ge grabber amongst the sur- 

 viving past Presidents, has been confided to an amateur. 



Under these circumstances I should be untrue to myself and 

 to you, if I pre-umed to address you as one conversant with 

 CTeoorai hy in any extended signification of the word, or if I 

 attempted to deal with that imporlant and attractive branch of 

 it, topographical discovery, which claims more or less exclu- 

 sively the time and attention of the geogi-aphers of thi-- country. 

 It is more fitting for me, and more in keei'ing with the objects 

 of this Association, that I be allowed !o discourse before you on 

 one of the many branches of science the pursuit of which is 

 involved in the higher aims of geographers, and which, as we 

 are informed by an accompkshed cultivator of the science, are 



