208 THE AMERICAN NATURALIST. [Vol. XXXVII. 



called ambiguous all results which gave a shorter sensory reaction 

 time. Professor Baldwin also very interestingly shows, in another 

 essay, that his theory fits in well with the facts of sensory and motor 

 aphasias. 



The other experimental papers are of no great importance. The 

 Fragments close with five short papers on miscellaneous subjects. 

 The volume is admirably printed and bound, but on the whole the 

 essays themselves are of such slight permanent value as hardly to 

 justify a second publication in this form. 



Theoretical Biology. — Professor Reinke of Kiel has written 1 an 

 introduction to theoretical biology which treats of the fundamental 

 biological problems in their metaphysical aspects. The work is thus 

 predominantly philosophical in its purpose and form. He discusses 



tation, its content, origin and inheritance. The concepts of matter, 

 energy, force, law, and form in their relation to organization as seen 

 in the living world are discussed at length. The author introduces 

 the idea of dominants or "unbewusst intellegenten Krafte " as sup- 

 plementary to the energy which operates by chemical processes the 

 highly differentiated mechanism of the living organism. Dominants 

 are not identical, in the author's view, with the old vital force, but 

 like the mechanism have their basis in the structure of the organism. 

 The biological sections of the work all of which are correlated with the 

 fundamental problems discussed elsewhere deal with the attributes 

 and functions of protoplasm and the cell and with the development 

 and differentiation of organisms. Incidentally the problems of sex- 

 uality, fertilization and heredity are touched upon. In closing, the 

 author calls attention to the similarity of his views and those of 

 Johannes Miiller. The illustrative matter is drawn largely from 

 botanical sources. The scope of the work and the clearness with 



l Reinke, J. Eiiihituiig in ,//? theorethche liiolo^e. Pp. xv, 637. Mit. 83 



