316 GOLGI BODIES ETC. 



The following modification in staining has been used with 

 success. After bleaching sections, and thoroughly washing, 

 Altmann's anilin acid fuchsin is poured on the slides, which 

 are heated until steaming occurs. They are then allowed to stand 

 for half an hour. The excess stain is finally washed off with 

 distilled water, and the slides are brought direct to absolute 

 alcohol in which they are differentiated (Ludford, Jour. R.M.S., 

 1926, pp. 107—109). 



In a series of experiments carried out with tumour cells it was 

 found that the length of time a tissue remains in the Mann's 

 fluid has practically no effect upon the subsequent impregnation 

 of the Golgi apparatus with osmic acid (Ludford, Jour. R.M.S., 

 1924, pp. 269 — 280). When the pieces have remained for longer 

 periods in Mann's fluid, however, sublimate crystals may be formed 

 in the tissues. These can be removed by treating the sections 

 with Lugol's solution. 



The Mann-Kopsch technique can be used in combination with 

 the Kull staining method (§ 695). We find that the cells are rather 

 liable to overstrain in the toluidin blue, which must be left on for 

 a very short time. 



Explanation. Mann's osmo-sublimate fixes the cells successfully, 

 because the HgClj aids penetration and the OsOj is not so concentrated 

 as to cause shrinkage. Thus, before the tissue is transferred to the 

 Kopsch fluid (OSO4 of 2 per cent.), a complete fixation has taken place 

 and the distorting effect of the strong OSO4 is avoided. Left for two 

 weeks, the lipoid materials which partly form the substance of the 

 Golgi apparatus, the unsaturated fats, and the special lipoids of the 

 mitochondria, are all able to reduce the OSO4 in varying degrees. The 

 subsequent treatment of the sections by turpentine (oxidiser) introduces 

 a further differentiation, and so the various inclusions can be dis- 

 tinguished. The acid fuchsin stains presiunably the lipoid content of 

 the mitochondria. 



712. Shorter Osmication Methods. The length of J:ime taken 

 by osmic acid to penetrate tissues and impregnate the Golgi 

 apparatus has led to various modifications of the Kopsch method 

 being employed to bring about the result in a shorter time. Experi- 

 ments have shown that reduction of the osmic acid is considerably 

 hastened by a moderate rise of temperature. In well-fixed 

 material, however, there are considerable secondary changes in 

 the cytoplasm on incubation in w^atery media, at temperatures 

 ranging from 40° to 60° C. (Ludford, Jour.R.M.S., 1924, pp. 269— 

 280). This fact renders it undesirable to employ temperatures 

 much above 35° C. 



Of the methods in which hot osmic acid is employed the follow- 

 ing have been found to give excellent results : — 



713. The Kolatchew Method as Modified by Nassonow. The 

 material is fixed in Champy's fluid to each 10 c.c. of which 2 or 



