Literary Notices. xiii 



cated that the olfactory pero is not an integral pait of the brain but an 

 ingrowth from without. 



With reference to the function of the so-called protcpla.'-mic pro- ' 

 cesses we cjuote from Van Gehuchten as follows : "This example of 

 nervous transmission by contact afforded by the olfactory bulb is interest- 

 ing from another point of view. It casts, in effect, a bright light on the 

 physiological role of the protopla.^mic prcces-^es of the nerve cells. Ac- 

 cording to Golgi, these prolongations come into intimate relation with the 

 blood vessels and serve solely for the nutrition of the nervous elements 

 and have no share in the transmission of a nerve stimulus. The latter 

 function pertains solely to the cell body and axis-cylinder processes, which 

 Golgi accordingly designates as the functional processes. Ramon y Cajal 

 opposed this view; the structure of the olfactory bulb indicates clearly 

 that the protoplasmic processes communicate with the axis-cylinder pro- 

 cesses. Kolliker has not discussed this question. We have verified all 

 the statements of Ramon y Cajal, and we admit with him that the whole 

 nervous element is active in the transmission of the stimulus, the proto- 

 plasmic processes and the body of the nerve cell receive the stimulus from 

 the axis cylinder of an adjoining cell and transmit it thrcugh its own axis- 

 cylinder to other nervous elements. The absolute independence of the 

 nervous elements and, as a natural consequence, the transmission of nerve 

 stmuli by contact is thus verified in all the various parts of the cerebro- 

 spinal axis." 1 



Until quite recently the application of Golgi's rrelhod to invertebrate 

 tissues has proven unsuccessful. But hand and hand with the development of 

 the methyl blue /«/ra wV'aw staining introduced by Erlici, which has afford- 

 ed such wonderful results in the hands of Retzius, has gone the application 

 of the silver method to the nervous tissues of lower animals. A beautiful 

 illustration of the connection between the most widely separated regions 

 of comparative anatomy is afforded by the results obtained by Lenhossek 

 with Golgi's method applied to the earth worm. - 



The author summarizes his results as follows : "The sensoiy nerve 

 cells, i. e., those elements which correspond to the spinal ganglion cells of 

 vertebrates and give rise to the sensory peripheral fibres are found r either 



1. Les decouverte.s recentes dans 1' anatoiiiie et I' histologic, etc., 1S91, p. 41. 



2. MicHEAL Von Lenhossek. Ursprung, Verlauf und Endigung der sensibelu 

 Kervenfasern bei Lumbricus. Archiv f. Mikio.'kcpische Aiiatcniie, XXXIX, p. 1C2 — 

 136. Plate V. 



