84 REVIEW OF THE GOLGI METHOD. 



delicacy, the reaction being, so to speak, tumultuous, but gradually 

 gains in fineness with progressive hardening (always, however, 

 after a more or less brief period of time). Tlien the individual 

 fibres (axis cylinders) composing the bundles can be vvell seen, 

 and also individual fibrillae streaming from the bundles, the finest 

 details of whose course and branching can be seen at a glance. 



" 2. — The ganglion cells. The ganglion cells of the superficial 

 layers always stain first {e.g.^ in the cortex the small cells of the 

 peripheral zone), but at the same time with t"hem also some cells 

 irregularly scattered in the inner layers. As the reaction pro- 

 gresses, it afiects the cells rather than the fibres, and the tendency 

 is for the stain of the cells to become more general and to 9xtend 

 from the periphery inwards. Then, too, while the reaction is 

 becoming more complete among the cells of the deeper layers, it 

 becomes always more limited among those of the superficial layers. 



" With the cells as with the fibres, the reaction is at first coarse 

 and little fitted to bring to view certain interesting details. For 

 example, the nervous process is not stained at first to any great 

 extent, and usually only a short piece of it is to be seen, so that 

 neither its course, direction, nor its few or numerous branches can 

 be perceived. With the gradual progress of the reaction the 

 nerve-cells are displayed more clearly, and the finest subdivisions 

 of their protoplasmic as well as their nervous processes appear. 



" 3. — Cells of the netcroglia. — An interesting reaction occurs in 

 the cells of the neuroglia ; it may be said that it takes place in 

 pieces suitably hardened in bichromate from the beginning of the 

 phase to the end. In fact, at both the time when the fibres pre- 

 dominate and when the cells predominate, individual neuroglia 

 cells or groups of them are to be seen showing the characteristic 

 reaction of the silver nitrate (coffee-brown or yellowish). Besides, 

 with this species of element the reaction only becomes fine and 

 diffused in a somewhat advanced period of hardening, so that 

 their typical form and relations are plain. The reaction in neu- 

 roglia cells takes place for a long time beyond the time favourable 

 for staining nerve-cells. 



" The finest reaction for the nerve-cells, especially for the nerv- 

 ous processes, occurs at a somewhat advanced stage of hardening, 

 namely, when, with the advance of the reaction among neuroglia 



