Strong, Rcviciv of the Gol^i Method. 109 



possible, to attain this. This difficulty will be readily compre- 

 hended when one reflects that the diversity of results is brought 

 about not only by the conditions given already but also by the 

 unequal hardening action of the bichromate so that the individ- 

 ual layers of the pieces are in different conditions. In the 

 individual pieces the degree of hardening may increase from 

 center to periphery so that a number of the above combina- 

 tions and gradations may appear in one piece. 



"The following approximate rule, however, may be accept- 

 ed for the way the reaction enters the various elements of the 

 nervous tissue wlien a number of similar pieces are successively 

 subjected to the action of the silver nitrate. There stain in the 

 following order : 



"I. The bundles of Jierve fibers. At the same time with 

 the staining of these fibers some scattered ganglion cells which 

 lie dispersed in the gray matter appear. 



"The staining of the nerve fibers at the beginning shows 

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

 gradually gains in fineness with progressive hardening (always, how- 

 ever, after a more or less brief period of time). Then the individual 

 fibers (axis-cylinders) composing the bundles can be well 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 su- 

 perficial layers always stain first (e. g. in the cortex the small 

 cells of the peripheral zone), but at the same time with them 

 also some cells irregularly scattered in the inner layers. As the 

 reaction progresses it affects the cells rather than the fibers 

 and the tendency is for the stain of the cells to become more 

 general and to extend 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 fibers the reaction is at first 

 coarse and little fitted to bring to view certain interesting de- 

 tails. 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 



