684 



SCIENCE 



[N. S. Vol. XLIV. No. 1141 



Fig. 4, are very different from those shown in 

 Fig. 5. The latter figure plainly does not 

 come from observations in the open lake. This 

 can not fall to 4° by December 1; nor can 

 the surface maintain a temperature of nearly 

 30° in July. The discussion of the thermo- 

 cline shows that the authors' interests are 

 primarily elsewhere than with temperatures. 



But such matters do not detract from the 

 general value of the book, both for students 

 and as a contribution to limnology. 



A word must be said of the illustrations 

 which, in general, are extraordinarily good. 

 Sometimes photography is pushed too far. 

 Not a few photographs of insects, etc., are 

 from objects so dark that they do not show 

 necessary detail. In such cases a drawing 

 would do much better service. But a great 

 many of the photographs, such as Big. 61 — 

 duck-meat — and Big. 207 really illustrate the 

 subject and tell the student in the study what 

 he ought to see in the field. 



E. A. Birge 



Individuality in Organisms. By Charles 

 Manning Child, Brofessor of Zoology in the 

 University of Chicago. The University of 

 Chicago Bress, 1915. Bp. 213. $1.25 net. 

 What is the nature of the unity and order 

 which characterize the organic individual? 

 Upon the basis of fifteen years of experimental 

 and analytical investigation Brofessor Child 

 in his recent book on " Individuality in Or- 

 ganisms " attempts to give an answer to this 

 important problem. 



In the first chapter of the book the writer 

 makes clear that he is dealing with the prob- 

 lem of physiological individuality exclusively 

 without metaphysical assumptions. Current 

 hypotheses of the individual are found either 

 to ignore the problem of the unity and order 

 within the organism, or they carry with them 

 vitalistic implications. His criticism of these 

 hypotheses in chapter two forms one of the 

 most readable portions of the book. 



In place of current " corpuscular " theories 

 of the individual which postulate " a mysteri- 

 ous, self-determined organization in the proto- 

 plasm, cell or cell-mass," Brofessor Child 



would substitute a dynamic conception of the 

 individual. Bhysiological unity and order in 

 his opinion are to be interpreted not in terms 

 of a hypothetical organization and the trans- 

 portation of chemical substances within the 

 organism, but in terms of differences in the 

 rate of reaction and of transmitted change. 

 The basis of individuality lies in " spatial 

 quantitative differences in the action of ex- 

 ternal factors on protoplasm." He finds ex- 

 perimentally that the head of the animal and 

 the growing tip of the plant are centers of 

 more active metabolism while posteriorly or 

 basally processes are less intense. This evi- 

 dence has led him to his doctrine of metabolic 

 gradients, proof of the existence of which is 

 advanced in chapter three. 



Concluding that " the organic individual is 

 fundamentally a dynamic relation of domi- 

 nance and subordination, associated with and 

 resulting from the establishment of a meta- 

 bolic gradient or gradients," Dr. Child in sub- 

 sequent chapters presents evidence of domi- 

 nance within the organism and discusses the 

 limitations of its range. Dominance in the 

 individual is determined primarily, not by 

 means of the transportation of chemical sub- 

 stances from one organ to another, but through 

 the transmission of impulses just as in the 

 nervous system. Subsequent to organic dif- 

 ferentiation in ontogeny, however, integration 

 of the organism may be partly effected through 

 the transportation of chemical substances. 



The bearings of the hypothesis upon the 

 problems of differentiation, reproduction, he- 

 redity and evolution are suggested and briefly 

 discussed in the concluding chapter of the 

 book. 



The claims of the author for his hypothesis 

 are modest. It is certainly not too much to 

 say that it has already proved its value as " a 

 basis for the synthesis and ordering of many 

 facts in various fields which heretofore have 

 seemed to have little or nothing in common" 

 and that it has brought " certain aspects of 

 biology within hailing distance of physico- 

 chemical conceptions." Adverse criticism has 

 been largely forestalled by the objections 

 which Dr. Child has himself raised and an- 



