September 14, 1S93] 



NA TURE 



467 



more fully on the scienliric history of the time, we should, I 

 think, find the clearest evidence, first, that the foundation was 

 laid in anatomical discoveries, in which it is gratifying to re- 

 member that English anatomists (Allen Thomson, Bowman, 

 Goodsir, Sharpey) took considerable share ; secondly, that 

 progiess was rendered possible by the rapid advances which, 

 during the previous decade, had been made in physics and 

 chemistry, and the participation of physiology in the general 

 awakening of the scientific spirit which these discoveries pro- 

 duced. 1 venture, however, to think that, notwithstanding the 

 operation of these two causes, or rather combinations of causes, 

 the development of our science would have been delayed had it 

 not been for the exceptional endowments of the four or five 

 young experimenters whose names I have mentioned, each of 

 whom was capable of becoming a master in his own branch, 

 and of guiding the future progress of inquiry. 



Just as the affinities of an organism can be best learned from 

 its development, so the scope of a science may be most easily 

 judged of by the tendencies which it exhibits in its origin. J 

 wish now to complete the sketch I have endeavoured to give of 

 the way in which physiology entered on the career it has since 

 followed for the last half-century, by a few words as to the in- 

 fluence exercised on general physiological theory by the progress 

 of research. We have seen that no real advance was made 

 until it became possible to investigate the phenomena of life by 

 methods which approached more or less closely to those of the 

 physicist, in exactitude. The methods of investigation being 

 physical or chemical, the organism itself naturally came to be 

 considered as a complex of such processes, and nothing more. 

 And in particular the idea of adaptation, which, as I have en- 

 deavoured to show, is not a consequence of organism, but its 

 essence, was in great measure lost sight of. Not, I think, 

 because it was any more possible than before to conceive of the 

 organism otherwise than as a working together of parts for the 

 good of the whole, but rather that, if I may so express it, the 

 minds of men were so occupied with new facts that they had not 

 time to elaborate theories. The old meaning of the term 

 "adaptation" as the equivalent of "design" had been 

 abandoned, and no new meaning had yet been given to it, 

 and consequently the word " mechanism " came to be employed 

 as the equivalent of " process," as if the constant concomitance 

 or sequence of two events was in itself a sufficient reason for 

 assuming a mechanical relation between them. As in daily life 

 so also in science, the misuse of words leads to misconceptions. 

 To assert that the link between a and his mechanical, for no 

 better reason than that b always follows a, is an error of state- 

 ment, which is apt to lead the incautious reader or hearer to 

 imagine that the relation between a and b is understood, when 

 in fact its nature may be wholly unknown. Whether or not at 

 the time which we are considering, some physiological writers 

 showed a tendency to commit this error, I do not think that it 

 found expression in any generally accepted theory of life. It 

 may, however, be admitted that the rapid progress of experi- 

 mental investigation led to too confident anticipations, and that 

 to some enthusiastic minds it appeared as if we were approaching 

 within measurable distance of the end of knowledge. Such a 

 tendency is, I think, a natural result of every signal advance. 

 In an eloquent Harveian oration, delivered last autumn by Dr. 

 liridges, it was indicated how, after Harvey's great discovery of 

 the circulation, men were too apt to found upon it explanations 

 of all phenomena whether of health or disease, to such an extent 

 that the practice of medicine was even prejudicially affected by 

 ■t. In respect of its scientific importance the epoch we arecon- 

 ■ idering may « ell be compared with that of Harvey, and may 

 have been followed by an undue preference of the new as com- 

 pared with the old, but no more permanent unfavourable results 



' have shown themselves. As regards the science of medicine we 

 need only remember that it was during the years between 1845 

 and i860 that Virchow made those researches by which he 

 Irought the processes ofdisease into immediate relation with the 

 n'lrmal processes of cell-development and growth, and so, by 

 iking pathology a part of physiology, secured its subsequent 

 .gress and its influence on practical medicine. Similarly in 

 physiology, the achievements of those years led on without any 



I interruption or drawback to those of the following generation ; 

 while in general biology, the revolution in the mode of regarding 

 the internal processes of the animal or plant organism which 

 resulted from these achievements, prepared the way for the 



: acceptance of the still greater revolution which the Darwinian 

 epoch brought about in the views entertained by naturalists of 



NO. I 246, VOL. 48] 



the relations of plants and animals to each other and to their 

 surroundings. 



It has been said that every science of observation begins by 

 going out botanising, by which, I suppose, is meant that col- 

 lecting and recording observations is the first thing to be done 

 in entering on a new field of inquiry. The remark would 

 scarcely be true of physiology, even at the earliest stage of its 

 development, for the most elementary of its facts could scarcely 

 be picked up as one gathers flowers in a wood. Each of the 

 processes which go to make up the complex of life requires 

 separate investigation, and in each case the investigation must 

 consist in first splitting up the process into its constituent 

 phenomena, and then determining their relation to each other, 

 to the process of i> hich they form part, and to the conditions 

 under which they manifest themselves. It will, I think, be 

 found that even in the simplest inquiry into the nature of vital 

 processes some such order as this is followed. Thus, for 

 example, if muicular contraction be the subject on which we seek 

 iiifurmation, it is obvious that, in order to measure its duration, 

 the mechanical work it accomplishes, the heat wasted in doing 

 it, the electro-motive forces which it develops, and the changes 

 of form associated with these phenomena, special modes of 

 observation must be used for each of them, that each measure- 

 ment must be in the first instance separately made, under special 

 conditions, and by methods specially adapted to the required 

 purpose. In the synthetic part of the inquiry the guidance of 

 experiment must again be sought for the purpose of discriminat- 

 ing between apparent and real causes, and of determining the 

 order in which the phenomena occur. Even the simplest 

 experimental investigations of vital processes are beset with 

 difficulties. For, in addition to the extreme complexity of the 

 phenomena to be examined and the uncertainties which arise 

 from the relative inconstancy of the conditions of all that goes 

 on in the living organism, there is this additional drawback, 

 that, whereas in the exact sciences experiment is guided by well- 

 ascertained laws, here the only principle of universal application 

 is that of adaptation, and that even this cannot, like a law of 

 physic?, be taken as a basis for deductions, but only as a 

 summary expression of that relation between external exciting 

 causes and the reactions to which they give rise, which, in 

 accordance with Treviranus' definition, is the essential character 

 of vital activity. 



The Specific Energies of the Organism. 

 When in 1826 J. Miiller was engaged in investigating the 

 physiology of vision and hearing he introduced into the discus- 

 sion a term "specific energy," the use of which by Helmholtz' 

 in his physiological writings has rendered it familiar to all 

 students. Both writers mean by the word energy, not the 

 " capacity of doing work," but simply activity, using it in its 

 old-fashioned meaning, that of the Greek word from which it is 

 derived. With the qualification "specific," it serves, perhaps, 

 better than any other expression to indicate the way in which 

 adaptation manifests itself. In this more extended sense the 

 "specific energy " of a part or organ— whether that part be a 

 secreting cell, a motor cell of the brain or spinal cord, or one of 

 the photogenous cells which produce the light of the glowworm, 

 or the protoplasmic plate which generates the discharge of the 

 torpedo — is simply the special action which it normally performs, 

 its norma or rule of action being in each instance the interest of 

 the organism as a whole of which it forms part, and the exciting 

 cause some influence outside of the excited structure, technically 

 called a stimulus. It thus stands for a characteristic of living 

 structures which seems to be universal. The apparent excep- 

 tions are to be found in those bodily activities which, following 

 Bichat, we call vegetative, because they go on, so to speak, as 

 a matter of course ; but the more closely we look into them the 

 more does it appear that they form no exception to the general 

 rule, that every link in the chain of living action, however 

 uniform that action may be, is a response to an antecedent in- 

 fluence. Nor can it well be doubted that, as every living cell or 

 tissue is called upon to act in the interest of the whole, the 

 organism must be capable of influencing every part so as to regu- 

 late its action. For, although there are some instances in which 

 the channels of this influence are as yet unknown, the tendency 

 of recent investigations has been to diminish the number of such 

 instances. In general there is no difficulty in determining both 

 the nature of the central influence exercised and the relation 



' " Handb. der physiologischcn Optik," 1886, p. 233. Helmholtz uses 

 the word in the plur.il — the '* energies of the nerves of special sense." 



