A REVIEW OF THE GOLGI METHOD. 165 



ologische Bedeutung '' (from the Rendiconti des R. Instituto Lofn- 

 bardo^ Ser. II., Vol. XXIV., Fasc. 8 and 9), pp. 259 and 260 of 

 the German edition of Golgi's works : 



" The Method which was most useful to me in the investiga- 

 tions described in the first part of this work, was the staining of 

 the nervous elements with mercury sublimate, but with a modifi- 

 cation which enhanced its demonstrative value without changing 

 the fundamental procedure. The latter consists (i) in the hard- 

 ening of the pieces in bichromate of potassium ; (2) in the 

 transference from this into a ^ per cent, to i per cent, solution 

 of bichloride of mercur3^ 



"Since I have given in another work (' Studi sulla fina ana- 

 tomia degli organi centrali del sistema nervoso,' p. 202) a detailed 

 description of what I call the fundamental part of the method, I 

 consider it fitting to add that the best and finest reactions in the 

 nerve fibres and the interstitial diffuse network was observed by 

 me in pieces (from the spinal cord of the new-born kitten) which 

 had lain a long time (in part over two years) in a i per cent, 

 solution of sublimate, after a long preceding sojourn in a bichro- 

 mate solution (first, Miiller's fluid ; then, pure bichromate to 3 per 

 cent). Since they were pieces which had lain in the laboratory 

 in this way ready for examination but had not been used, I can, 

 naturally, not tell what influence the long sojourn in the sublimate 

 may have exerted. 



"The modification introduced by me, to which I must attribute 

 a certain value for the clear demonstration of fine details, and to 

 which I call the attention of the observer, consists simply in a 

 slight addition, viz., the blackening of the glistening white stain 

 which the nerve elements receive by means of the mercury im- 

 pregnation. 



" As is known, the elements treated with sublimate appear 

 black in transmitted light, on account of the opacity caused by 

 the reaction, but in reflected light they appear white. This 

 difference may be easily observed by turning off the mirror of 

 the microscope. 



" This kind of appearance is satisfactory for observation with 



low or medium magnification, where less fine details are concerned, 



but it is otherwise with the finer details, where stronger magnifica- 



International Journal of Microscopy and Natural Science. 

 Third Series. Vol. VII. m 



