870 TRANSACTIONS OP SECTION I. 



asserts or maintains a specific structure and specific activities, it Is clear tbat 

 nutrition itself is only a constant process of reproduction : for the material of the 

 organism is constantly changing. Not only is there constant raolecu'ar change, 

 but the living cells are constantly being cast oil and reproduced. It is only a 

 step from this to the reproduction of lost parts which occurs so readily among 

 lower organisms ; and a not much greater step to the development of a complete 

 organism from a single one of the constituent cells of an embryo in its early 

 stages. In all these facta we have simply manifestations of the fundamental 

 characters of the living organism. The reproduction of the parent organism from 

 a single one of its constituent cells separated from the body seems to me only 

 another such manifestation. Heredity, or, as it is sometimes metaphorically ex- 

 pressed, organic memory, is for Biology an axiom and not a problem. The problem 

 is why death occurs, what it really is, and why only certain parts of the body are 

 capable of reproducing the whole. These questions carry us, at least in part, 

 beyond the present boundary lines of Biology. They involve those ultimate 

 questions which, as has just been pointed out, it is the province of Philosophy 

 to deal with. 



To turn to another set of questions, the distincti%-ely biolo^i al standpoint in 

 Biology involves a change in what has in recent times become the ordinary 

 attitude towards organic evolution. Since our conception of an organism is 

 different in kind, and not merely in degree, from our conception of a material 

 aggregate, it is clear that in tracing back life to primitive forms we are 

 getting no nearer to what is called ablogenesis. The result of investigation in 

 this direction can only be to extend further the domain of Biology and widen 

 biological ideas. Our aim must be, in short, not to reduce organic to inorganic 

 phenomena, but to bring inorganic phenomena into the domain of Biology. 



I am well aware that it will be strongly maintained that the change of front 

 which I have urged as necessary involves the giving up of all real attempt at 

 scientific explanation in Biology. As already explained, this is a philosophical 

 question, and I shall not attempt to deal further with it here. What immedi- 

 ately concern* us as biologists is whether the change of front will further or hinder 

 biological advance, particularly in Physiology. Now the first requisite of a 

 working hypothesis is that it should woVk, and I have tried to point out that as 

 a matter of fact the physico-chemical theory of life has not worked in the past 

 and can never work. As soon as we pass beyond the most superficial details of 

 physiological activity it becomes unsatisfactory ; and it breaks down completely 

 when applied to fundamental physiological problems, such as that of reproduction. 

 Those who aim at physico-chemical explanations of life are simply running their 

 heads at a stone wall, and can only expect sore heads as a consequence. It 

 seems to me that the proposed change of front is only the conscious adoption of a 

 common-sense idea which is somewhat vaguely, perhaps, present in the minds of 

 all men, and which has in reality guided biological advance in the past. This 

 idea, as I have tried to show, is a working hypothesis which actually worlis, and 

 affords clear guidance for future advance. 



I would fain add a few words as to the relation of Physiology to Psychology 

 and Ethics : for this is a subject of deep human interest. We know that at any 

 rate the higher organisms are conscious and intelligent. This fact brings 

 Physiology into touch with a new element in the behaviour of organisms. The 

 subject is far too great a one for me to attempt to discuss here, but I should like 

 to say that it appears to me very clear that just as Biology is something more 

 than Physics and Chemistry, so Psychology is something more than Physiology, 

 with the added assumption that consciousness is tacked on to certain physiological 

 processes, if such a crude conception has any definite meaning. We can, it is 

 true, by a process of abstraction treat sensation from the purely physiological side, 

 as in investigating the physiology of the sense-organs ; but this is Physiology 

 and nothing else; for we are leaving out of account the distinctive elements of 

 consciousness. At our present stage of knowledge life is not intelligence, and 

 men or animals as intelligent individuals involve a deeper aspect of reality 

 than Biology deals with. Our fundamental physiological working hypothesis 



