A REVIEW OF THE GOLGI METHOD. 157 



is, perhaps, an advantage in so far as one can with sureness obtain 

 certain preparations for demonstrations in a tolerably brief time. 

 But the advantage is not extended to the fineness of the result, 

 since in all such preparations the reaction turns out rather coarse. 

 I was not thereby encouraged to extend experiments in this direc- 

 tion, especially as the abbreviation of the time can be attained in 

 other simpler ways, and as the pieces in the chamber quickly pass 

 by the period favourable to the success of the reaction without 

 attaining the kind of hardening sought — which is a not insignifi- 

 cant disadvantage. 



" {c) Hardening in ErlickVs fluid (bichromate of potassium, 

 2^^ g. ; copper sulphate, >^ g.; distilled water, loog.)- Regarding 

 this I confine myself to stating that the copper salt added to the 

 bichromate did not prevent the reaction, and that the Erlicki's 

 fluid possessed the same advantages and disadvantages as the 

 preceding method (warm chamber). It accelerates the hardening 

 so that in a few days (6 to 8 to lo) the black stain of various 

 elements of the nervous system can be obtained by transferring to 

 silver, but the result cannot be commended for fineness. More- 

 over the period advantageous for the reaction is very quickly 

 passed over. 



" As it appeared to me that the limited and not very fine form 

 of the reaction might be due in part to the rapid action of the 

 hardening fluid, I weakened the same by mixing it in gradually 

 increasing quantities with Miiller's fluid (Erlicki 20 to 50 per cent , 

 Miiller 30 to 50 per cent.). The results obtained by means of 

 this variation were decidedly good. After only 5 to 6 to 8 days' 

 immersion in such a fluid I obtained preparations which, in regard 

 to fineness of result, had a certain worth. It thus appears to me 

 that this variation can be recommended for the purpose of quick 

 demonstrations of cell-forms. For the finest details, especially 

 the relation of the functional processes of the ganglion cells and 

 the nerve fibres, I find that the first procedure is always to be 

 preferred, or also the following : 



" 2. — Method of the successive actions of a mixture of osmic acid 

 with bichromate and of the silver nitrate. This procedure also is 

 only a modification of the original, but deserves a place in the 

 exposition as a method by itself, partly because the not unimportant 



