426 CHAPTER XXXII. 



can be demonstrated by the silver-nitrate method, but it is 

 superior to it in that the reaction can always be obtained 

 with perfect certainty in a certain time ; that the prepara- 

 tions can be perfectly preserved by the usual methods ; and 

 that large pieces of tissue can be impregnated. 



See also FLATATJ, in Arch.f. mik. Anat., xlv, 1895, p. 158; Zeit.f. wiss. 

 Mik., xii, 2, 1895, p. 257. 



The method is recommended by BLOCHMANN (Biol. Centralb., xv, 1895, 

 p. 14 ; Zeit. f. wiss. Mik., xii, 2, 1895, p. 226) for the nervous system of 

 Oestodes. 



Modifications of G-olgi's Bichromate and Sublimate Method. 



764. TAL (Gazz. degli Ospiiali, 1886, No. 68) finds that if sections made 

 by this process be treated with solution of sodium sulphide, a much darker 

 stain is obtained. Sections may then advantageously be double-stained with 

 Magdala red. 



Golgi's method may be combined with Weigert's nerve stain (see PAL, 

 Wien. med. Jahrb., 1886 ; Zeit.f. wiss. Mik., v, 1, 1887, p. 93). 



765. Cox (Arch.f. mik. Anat., xxxvii, 1891, p. 16; Journ. 

 Roy. Mic. Soc., 1891, p. 420) finds the sublimate and bichro- 

 mate may be used together, and give a uniform impregnation. 

 He used a fluid consisting of 20 parts 5 per cent, bichromate, 

 20 parts 5 per cent, sublimate, 16 parts 5 per cent, simple 

 chromate of potash, and 30 to 40 parts of water. (The 

 simple chromate should be added to the other ingredients 

 only after diluting with the water.) The mixture should be 

 as little acid as possible. The duration of the impregnation 

 is from two to three months. There is considerable difficulty 

 in preserving sections, which mast be made with a freezing 

 microtome, alcohol being avoided, treated for an hour or two 

 with 5 per cent, solution of sodium carbonate, and mounted 

 without a cover. 



Dr. A. SANDERS, on the other hand, writes me (June, 1898) that the stain 

 keeps very well if the sublimate be well removed by washing in many 

 changes of alcohol, and the tissues passed through alcohol and ether into 

 celloidin, and the sections mounted in chloroform-balsam under a cover. I 

 think the statement is correct so far as regards the preservation of the 

 stain ; but the preparations quickly develop opaque granules that are very 

 unsightly. 



