194 



NATURE 



[October 22, 19 14 



known in the inorganic domain. Of course, we have 

 our psychical life, but can we say that this makes 

 a thoroughgoing' distinction between organisms and 

 inanimate bodies? How can we tell? Thus there 

 ends a masterly book — scholarly, keenly critical, 

 and rigidly objective. We do not think that the 

 author shows the sufficiency of chemico-physical 

 formulae for the description of the phenomena of 

 life, but we have the strongest admiration for his 

 searching criticism of the doctrine of the auto- 

 nomy of the organism. His book should be read 

 along with Johnstone's "Philosophy of Biology." 

 (2) "The time is now more than ripe," Dr. 

 Haldane writes, "for bringing the great biological 

 movement of the nineteenth century into definite 

 relation with the main stream of human thought," 

 and his lectures form an important contribution 

 towards the fulfilment of this task. The first 

 lecture contrasts the mechanistic and the vitalistic 

 interpretations. The former is certainly good so 

 far as it goes, for the living creature can be use- 

 fully considered as a very complex material 

 system, conforming to the laws of dynamics, ex- 

 hibiting physical an3 chemical processes that arc 

 in line with those of the inorganic world, and as 

 for consciousness (if that be demonstrable) it 

 makes no difference to the energy balance whether 

 the organism is conscious or not. It is true that 

 the activities of the organism are very wonder- 

 fully co-ordinated towards securing the survival 

 of the individual and the race, but it is replied that 

 there are effective nervous and chemical means 

 which secure this co-ordination, and have been 

 wrought out in the course of untold ages of varia- 

 tion and selection. It has to be admitted, how- 

 ever, that what goes on is more complicated than 

 the working of any machine known to man; that 

 mechanical interpretations of such functions as 

 excretion and respiration have had to be aban- 

 doned from time to time because they did not 

 cover the facts; that heredity, variation, and de- 

 velopment seem facts per se ; and that the 

 organism is strangely autonomous. For these 

 and similar reasons there is periodic reaction from 

 mechanism to vitalism. 



"Vitalism assumes that the intimate processes 

 are guided or controlled by an influence which is 

 manifested only in living organisms, and which 

 acts in a manner wholly different from anything 

 known in the inorganic world." 



To Dr. Haldane the theory of vitalism is no 

 more acceptable than that of mechanism. For if 

 a vital principle controls what goes on in the 

 organism, can it do so without a breach in the 

 conservation of energy ; and if it guides, how does 

 it know how to do it? The hypothetical vital 

 principle is unproved, unintelligible, and useless. 

 NO. 2347, VOL. 94] 



In this chapter, the answer to Driesch's argument 

 from embryonic development seems to us very far 

 from clear. 



The second lecture contains a criticism of the 

 mechanistic theory. It has been useful in stimu- 

 lating research, but it is inadequate for the re- 

 description of what is essentially vital. A minute 

 increase in the hydrogen ion concentration of the 

 blood induces an intense activity of the respira- 

 tory centre, but we do not know the chain of 

 events between the stimulus and the response. 



" In the case of stimulus and response there is 

 in reality no experimental evidence whatsoever 

 that the process can be understood as one of 

 physical and chemical causation." 



Or what are we to make of the "recovery of 

 functional activity after destruction of centres or 

 nerve paths on which this activity normally de- 

 pends?" Moreover, the fact is that "physico- 

 chemical explanations of elementary physiological 

 processes are as remote as at any time in the 

 past." Even if we could picture the vast assem- 

 blage of delicately-adjusted cell-mechanisms, 

 keeping themselves in working order year after 

 year, keeping in exact co-ordination with all the 

 other cell-mechanisms, and so on, how can we 

 conceive of this condensed into a germ-cell, uniting 

 with another germ-cell, and then developing 

 afresh. And the difficulty of thinking mechanic- 

 ally of reproduction recurs when we picture the 

 continual renewal of cells and plasm within the 

 body, the ceaseless work of maintaining a struc- 

 tural and functional specificity. Dr. Haldane 

 concludes that " the phenomena of life are of such 

 a nature that no physical or chemical explanation 

 of them is remotely conceivable." In speaking 

 of the mechanistic view of the germ-plasm, the 

 author says, p. 58 : "On the one hand we have to 

 postulate absolute definiteness of structure, and 

 on the other absolute indefiniteness. " But it 

 seems to us that the word indefiniteness is here 

 used in a sense not inconsistent with definiteness, 

 namely, in reference to the number of divisions 

 that may occur. If we understood one division, 

 we should not boggle over an indefinite number 

 of them. 



In his third lecture Dr. Haldane turns the 

 tables on the mechanists. The physical and 

 chemical concepts are, after all, but working 

 hypotheses ; the notion of a real and self-existent 

 material universe does not survive Hume's 

 criticism. In any case, when we pass to the 

 world of organisms we need new concepts, 

 especially that of the living organism, a specific 

 entity, actively maintaining and reproducing its 

 individual structure, with functions which are 

 determined in definite relation to the whole unified 



