REVIEWS 163 



physiology of the bivalve mollusca, the development of centra according to 

 Ridewood's results, and a revision of the Anthropology section following the 

 results of Elliot Smith, Ripley, and Keith. 



This book is particularly suitable for the large body of non-zoologists, such 

 as medical men, who would like to know something more about zoology and 

 comparative anatomy. J. B. G. 



The Nature of Animal Light. By E. Newton Harvey, Ph.D. [Pp. x + 182, 

 with 35 figures and 13 tables.] (Philadelphia and London : J. B. 

 Lippincott & Co., 1920. Price $3.50.) 



This, the fifth volume of the " Monographs on Experimental Biology," fully 

 maintains the high level set by the previous four, both in the matter presented, 

 the production and arrangement. Although it is probably realised in a 

 general way that " phosphorescence " has been studied to a certain extent, it 

 is only on reading a volume like the present with its extensive bibliography 

 and its wide treatment that the full significance and extent of the problem 

 becomes clear. The headings of the various chapters give a fair idea of the 

 scope of subject : — Light-producing Organisms, Luminescence and Incan- 

 descence, Physical Nature of Animal Light, Structure of Luminous Organs, 

 the Chemistry of Light Production, and the Dynamics of Luminescence. The 

 old term " phosphorescence," often used in regard to animals, should no 

 longer be employed. By the physicist this is applied to the phenomenon of 

 the emission of light by bodies after previous illumination or radiation, and 

 is not found in the animal world. It should be more accurately termed 

 chemiluminescence or oxyluminescence since it is absolutely dependent upon 

 a proper oxygen supply. Since in animals it is associated with structural 

 peculiarities as well as chemical ones, it is perhaps better to employ the term 

 bioluminescence to the phenomenon. In certain cases at any rate, it has been 

 shown that it is due to the interaction of two substances — Luciferin and Luci- 

 f erase — in the presence of water and oxygen. The two substances differ in 

 themselves, and are also slightly different in different animals. Luciferase is a 

 protein allied to the albumins, while Luciferin is not digested by proteolytic 

 ferments and is dialysable. 



Quite a large number of animals exhibit bioluminescence, and it is interest- 

 ing to note that their luminous efficiency may reach "96 as compared with the 

 •032 of a 600 c.p. 20 amp. metal filament electric lamp. 



The whole subject is one of great interest, and zoologists and comparative 

 physiologists are under a debt to Professor Harvey for the masterly way in 

 which he has included so much interesting matter within a comparatively 

 small compass. C. H. O'D. 



Amoeboid Movement. By Asa A. Sch^ffer, Ph.D. [Pp. vii + 156, with 46 

 illustrations.] (Princeton, U.S.A. : University Press, and Oxford 

 Press, 1920. Price $2.50.) 



As is well known. Professor Schaeffer has spent a great deal of time in studying 

 various species of Amceha from numerous points of view, and the present 

 volume is a statement of his observations and conclusions on the subject of 

 Amoeboid movement. Strangely enough, the discoverer of Amceba, Rosel v. 

 Rosenhof, when describing the animal in 1755, made one of the first and most 

 important observations on this physiological question. He pointed out that 

 the changes in form are associated with a streaming of the endoplasm. The 

 whole question is one of importance, since in Amceba we undoubtedly have a 

 quite primitive animal, and moreover, in view of the importance of the leuco- 

 cytes and phagocytes in the higher animals, anything that adds to our know- 

 ledge of their activities is to be welcomed. There is a considerable amount of 

 work on the question by numerous observers and all of this is reviewed critically 



