602 



SCIENCE 



[N. S. Vol. XXX. No. 77# 



now given its rightful place as one of the 

 important conditions of life on the earth's 

 surface. A paragraph is devoted to the muta- 

 tion theory. 



Many of the revisions in the present edition 

 occur in the chapter devoted to stimuli and 

 their actions. In a rediscussion of the action 

 of light rays on living substance the results of 

 Ilertel's vcork are presented approvingly, and 

 the general conclusions are reached that all 

 living- substance is sensitive to light as to 

 heat ; that light rays act upon living substance 

 primarily by altering metabolism through re- 

 duction processes; and that the question 

 whether the rays of any portion of the spec- 

 trum are physiologically active or not, is 

 merely a question of their intensity as radiant 

 energy, combined with the fact that the possi- 

 bility of the absorption of the rays by organ- 

 isms is inversely proportional to the wave- 

 length. Brief sections are devoted to the 

 physiological action of Eontgen and of Bec- 

 querel rays. The discussion of fatigue is 

 extended. New sections deal with the refrac- 

 tory stage of living substance in its relation 

 to stimuli, and the apparent increase in irrita- 

 bility which living substance experiences in 

 the early stages of stimulation. Great stress 

 is laid on the importance of Frohlich's ex- 

 planation of this latter phenomenon. It may 

 well be doubted whether the author has not 

 overestimated the value of this explanation. 



The final and heretofore long chapter on the 

 mechanism of life is still further extended in 

 the light of a fuller statement of the biogen 

 hypothesis. New sections deal with the ques- 

 tion of the role of oxygen in metabolism, the 

 self-regulation of metabolism and the law of 

 mass action, and functional and eytoplastic 

 metabolism. In a revision of the treatment 

 of inhibition the question whether the inhibit- 

 ing stimulus acts by augmenting anabolism 

 or depressing katabolism is answered in favor 

 of the latter view. Godlewski's experiment, 

 in which non-nucleated pieces of the ovum of 

 a sea urchin were fertilized by the spermatozoa 

 of a crinoid, and the resulting larvse possessed 

 purely maternal characteristics, is regarded as 

 an experimentum crucis demonstrating to a 

 certainty the incorrectness of the theory that 



the hereditary substance is localized in the cell 

 nucleus. The assumption that the nucleus is 

 the organ of oxidation for the cell is dismissed 

 as " blosse Pliantasie." 



It is only natural for an author to be best 

 acquainted with, and to look with favor on, 

 the products of his own laboratory and his 

 own country. No one can justly minimize 

 the invaluable contributions of Germany to 

 general physiology. But general physiological 

 research is now strikingly international, and 

 it is to be regretted that in so important a 

 book as Verworn's, the literature has not been 

 more widely canvassed. American, English 

 and French work is sadly neglected. Thus, of 

 the host of American investigators, only nine- 

 teen in all are cited, and of those who have 

 contributed during the past ten years of great 

 activity, only eight. Notwithstanding this 

 lack, Verworn's book is still the most compre- 

 hensive and stimulating of all works on gen- 

 eral physiology. Frederic S. Lee 



Columbia University 



The Opistholranchiate Mollusca of the Bran- 

 ner-Agassiz Expedition to Brazil. By 

 Frank Mace MacFarland. Stanford Uni- 

 versity Publications, University Series no> 

 2, 1909. 123 pp., 8vo, pi. i-xix. 

 During the work of the Branner-Agassiz 

 expedition to Brazil in 1899 a small collection 

 of Opisthobranchiate mollusca was made by 

 Mr. A. W. Greeley, a study of which forms 

 the basis of the present paper. This com- 

 prised seven species of which five are regarded 

 as new, one being a Pleurohranchus and the- 

 others nudibranchiata. 



Following the introduction the author gives 

 a list, with references, to thirty species of 

 Opisthobranchs, all yet reported from the east 

 coast of South America, Although this doubt- 

 less comprises only a moiety of the species 

 which may be expected to occur and is too 

 small to base extended generalizations upon,, 

 yet it indicates a fact already definitely shown 

 by collections of other groups of mollusks — 

 that the Antillean fauna extends for a consid- 

 erable distance southward along the coasts of 

 Brazil without interruption by the fresh 

 waters of the Amazon, which points to the- 



