462 Scientific Intelligence. 



their parasitic habits. Simple directions are given for distin- 

 guishing the injurious from the harmless species of the various 

 groups, for the protection of man and each of his domesticated 

 animals from the former, and for the treatment of persons or 

 animals suffering from these parasites. 



The book will not only serve as a guide to the study of insects 

 in relation to disease, but it is the most useful handbook available 

 for the sanitary officer, health inspector, nurse, and physician 

 in their professional duties. v^. R. c. 



2. Emhryology of the Chick; by Bradley M. Patten. Pp. ix, 

 167, with 182 figures.— Philadelphia, 1920(P. Blakiston's Son and 

 Co.). — This little book consists of an untechnical description of 

 the developmejit of the chick during the first four days of incuba- 

 tion, during which period the principal organ-systems of the body 

 are established. As it is designed particularly for the beginner 

 in the study of embryology, all unessential details have been 

 omitted and the discussion limited to the fundamental processes 

 involved. The well-executed and fully labelled diagrams make 

 as easy as possible the student's path through one of the most 

 difficult, although one of the most fascinating, fields of biology. 



w. R. c. 



3. University of Iowa Studies in Natural History: The Bar- 

 hados-Antigna Expedition; by C. C. Nutting. Pp. 274, with 

 50 plates. Iowa City, 1919 (published by the University). — This 

 is a delightful narrative of a collecting trip to the West Indies by 

 a party of teachers and advanced students from the zoological 

 department of the University of Iowa. The work of the party 

 from day to day and the discoveries of strange forms of marine 

 life which were made, as well as descriptions of the islands them- 

 selves, their natural resources, and the life of their human inhabit 

 tants, are recorded in a vivid style which bears witness not only to 

 the enthusiasm and skill of the author but also to the charms of 

 these wonderful tropical islands. In addition to the delightful 

 story of the expedition, the book is a real contribution to science, 

 for there are several chapters of zoological notes, recording obser- 

 vations on the habits of the terrestrial and marine animals of the 

 region. w. R. c. 



4. The Origin and Development of the Nervous Syustem 

 from a Physiological Vietvpoint ; by Charles Manning Child. 

 Pp. xvii, 296, with 70 text-figures. Chicago, 1921 (Tlie Univer- 

 sity of Chicago Press). — The author here applies to the develop- 

 ment of the nervous system his theory of axial gradients of 

 susceptibility. He shows that both the protoplasm and the 

 organism exhibit an ''organismic pattern" of physiological 

 gradients, the evolutionary development of which leads in the 

 higher animals to the complex excitation-transmission relations of 

 the nervous system; that is, ''from the simple physiological 

 gradient to the ego." With the support of extensive experi- 

 mental evidence and a consideration of all groups of organisms 



