GOLGI BODIES, ETC. 323 



(Da Fano), differentiating in 95 per cent, alcohol, safranin O. 

 (Griibler) saturated in equal parts of absolute alcohol and anilin 

 oil water, fifteen minutes to several hours, differentiating in 90 per 

 cent, alcohol. We have constantly used Mann's methyl blue eosin 

 in this laboratory. If iron-alum htcmatoxylin is to be used, the 

 alum bath must be short or the silver will be extracted, but Bowen 

 {Anat. Rec, 1928) says that if the sections be toned, see § 724, the 

 impregnation is unaffected. Bowen believes that this double 

 method has great possibilities. 



Of all these methods Mann's methyl blue eosin is the easiest and 

 best, as this fine stain usually acts normally on formalin material. 



728. On Toning Blue with Ferric Salts. In this laboratory J. S. 

 Barlee has used the following method to tone formalin silver nitrate 

 slides. The result is a blue preparation which has certain possibilities — 

 e.g. to discriminate between pigment and Golgi apparatus. Solution A. 

 Potassium ferricyanide 1-56 grm. H2SO4 concentrated 0-3 c.c., aq. dest. 

 1000 c.c. Solution B. Ferric ammonia citrate 1-56 grm. H2SO4 con- 

 centrated 3 c.c, aq. dest. 1000 c.c. Mix equal portions of A and B at 

 time of use. Bring slides to distilled water, add solution for about 

 fifteen minutes. Wash slides for at least ten minutes under tap after 

 toning. The stock solutions do not keep well. 



729. Difficulties and Faults in Formalin Silver Methods. Com- 

 plete failure to impregnate the Golgi apparatus sometimes occurs. 

 This may be due to bad or old formalin — ^commercial museum 

 formalin is useless. It may be due to the silver solution being too 

 old. Unless the previous trials have been successful, it is better 

 to make up new silver nitrate. Keep packets of silver nitrate 

 weighed up, so that the proper quantity can be placed in water 

 when new solution is needed. Reduction is naturally a vital 

 part of the method, one must see that this fluid is right. The 

 colour of quite efficient reducing solutions may vary from light to 

 dark sherry. Faults may be traced to the washing out after 

 fixation, and after silver nitrate. If one washes out too much 

 naturally the methods will not succeed, but this fault can be 

 guarded against by having a number of pieces of different sizes. 



Granulated preparations are usually due either to using too 

 strong silver nitrate, or to not washing out enough before reduc- 

 tion. Again, pieces of different thickness will help to solve the 

 difficulty. 



730. E. Vazquez Lopez Mixed Osmic-Silver Method for the Golgi 

 Apparatus (of Tissue Cultures) {Arch. Espcm. Oncologia, tonio III, 

 1932-33). 



Fix in osmic vapour for several minutes until the object becomes 

 opaque through the action of the vapour. Then wash well in distilled 

 water and submerge in 3 per cent, tannic acid for twenty-four hours at 

 room temperature. Transfer to a petrie dish with one drop of ammonia. 

 (Then place in Rio Hortega's ammoniacal silver reagent, j)repared by 

 adding to 30 c.c. of 10 per cent, silver nitrate, forty drops of 40 per cent, 

 caustic soda. The precipitate is allowed to settle, the supernatant 



11—2 



