Strong, Rcviezv of the Golgi Method. 1 1 7 



the exposition as a method by itself, partly because the not unim- 

 portant changes of the results which it yields and the treatment 

 which it requires are to be ascribed to the newly added re- 

 agent, partly because the process so modified can remedy some 

 inconveniences of the original method. 



" It can be applied in two ways, namely : 



" (a) By laying small pieces of nervous tissue directly in 

 a mixture of bichromate and osmic acid (2% to 2^% sol. of bi- 

 chromate, 8 parts ; i % sol. of osmic acic, 2 parts). 



"The black stain is obtained the most quickly with this 

 procedure. The black staining of a great number of nervous 

 elements can be obtained by transferring into silver at the second 

 or third day (see the directions for procedure in the description 

 of the original method). The reaction extends itself on the im- 

 mediately following days, then, as usual, diminishes and at the 

 tenth or twelfth day entirely ceases. 



"The treatment of the macro- and microscopical prepara- 

 tions which are obtained in this way must be considerably modi- 

 fied. Pieces prepared by this method differ from those prepared 

 by the first method inasnmch as when they are kept a long time 

 for future use, they become diffusely blackened and thereby use- 

 less. They must be kept in the same silver solution which has serv- 

 ed for the reaction. Then they are brought into pure alcohol, 

 which must be changed, where they remain not longer than two 

 days, sectioned and subjected to the above described treatment 

 (absolute alcohol with repeated washing, creosote, turpentine, 

 damar) necessary for their permanent preservation as micro- 

 scopical preparations. 



"Although this application of the osmium-bichromate 

 solution is certain and, as far as fineness is concerned, yields 

 satisfactory results; yet I find that for a systematic study of any 

 definite portion of the nervous system the following method is 

 far preferable: 



' ' (b) Bringing of fresh pieces into the bichromate solution ; 

 first transference into an osmitim-bichromate solution ; second trans- 

 ference into the silver solution. It is different with this second 

 procedure than with the preceding, in which the series of pieces 



