LITERARY NOTICES. 



Bethe, A. AUgemeine Anatomie und Physiologie de> Nciven>y>tems. Leip- 

 sig, G. Thieme, I903. pp. vii-4S5, 1)5 t^g^., 1 plate>. 



This volume is a series of monographs on diflerent phases of the 

 same subject rather than a textho<tk. of comparative neurology, as the 

 substance of many of the chapters rej)resents the author's own research. 

 The first three chapters are devoted to a historical account of the 

 structures of the nervou?; elements ; and in the comparative descrip- 

 tion of the nervous system (chapters 4 and 5), the structure and rela- 

 tion of these elements is given a more prominent j)lace than would be 

 pos.sible in a textbook. 



In all forms possessing a nervous system the neurofihrillae are the 

 essential nervous elements. The motor and sensorv fibrillae of inverte- 

 brates are connected by networks in the ganglion cells, and are also 

 continuous with each other in the neuropil. The nerve fibers of ver- 

 tebrates are composed of strands of fibrillae imbedded in jjerifibrillar 

 substance; at Ranvier's nodes the latter suV)stance is interruptetl, but 

 the fibrillae are always continuous. Fibrillar networks are formed 

 chiefly in the sensory ganglion cells; in most other cells the fibrillae 

 pass directly through ; they may enter by one dendrite and pass out 

 by another without entering the neurite of the cell. Bethe maintains 

 that motor and sensory fibrillae are j)ut into direct connection by the 

 "GoLOi nets" which envelop most of the central ganglion cells. 



The peripheral networks of cells and non-medullated fibers are 

 dealt with in chajiters 6 and 7. The entire nervous system of the 

 medusae is composed of these structures. They are also found in the 

 integument, vascular system and digestive tract of niollusks. arthro- 

 pods, worms and vertebrates. That these networks and not the muscles 

 are the true conducting elements of the medusae is shown by the fact 

 that two distinct bands of muscle may be made to contract Ity stimu- 

 lating one of them. If the entire central nervous system of a gastro- 

 pod mollusk is removed, stimulation of the b(»dy wall at one point will 

 produce a general muscular response. In a similar manner the applica- 



