GOLGI BODIES ETC. 315 



solution of glacial acetic acid). The excess of stain is then rinsed off 

 the slide with distilled water. After shaking off the distilled water, 

 absolute alcohol is poured on the sections. When the correct degree 

 of differentiation has been attained it is cleared in xylol and mounted 

 in balsam. 



We find that in successful Mann-Kopsch preparations, especially of 

 Invertebrata, the mitochondria do not generally become black, but are 

 either unstained or go yellowish. In many, but not all, cases it will be 

 found that where the mitochondria do become black after OSO4, 

 colour is more readily extracted from them than from the Golgi elements, 

 so that a distinction can nearly always be made by the Mann-Kopsch 

 method itself, without recourse to other methods which will generally 

 stain mitochondria and not Golgi apparatus (Regaud, Flemming, as 

 described in § 693). Among the most useful differentiation or extraction 

 methods after Mann-Kopsch, turpentine is probably the best. The 

 wax is removed from the sections on the slide by means of xylol, and the 

 slide is transferred to a jar of turpentine. After about half a minute the 

 section is examined under ^th inch objective, and the effect of the tur- 

 pentine is noted ; one sometimes finds that the black colour in fat 

 globules and yolk spheres is extracted before a quarter of an hour has 

 elapsed, while the Golgi apparatus retains its black condition. In most 

 cases it is therefore possible to distinguish between yolk and fat on the 

 one hand, and the Golgi apparatus on the other. 



711. Mann-Kopsch-Altmann Combination (Gatenby, Journ. 

 Roy. Micr. Soc.^ 1921). If examination of the first Mann- 

 Kopsch section showed that the Golgi apparatus was blackened, 

 and the mitochondria were either not stained or only straw or 

 light-brown coloured, one may proceed directly to the Altmann 

 stain. Should the examination show that the mitochondria as 

 well as the Golgi apparatus have become blackened, the sections 

 must be extracted in turpentine in an endeavour to remove the 

 blackening from the mitochondria. If the latter treatment does 

 not succeed properly the only course is to make new Mann-Kopsch 

 preparations, allowing less time in the OSO4, say seven or eight 

 days instead of the two weeks. 



When one has succeeded in procuring sections in which the 

 Golgi apparatus alone is blackened, it is possible to stain in 

 Altmann's anilin acid fuchsin and picric acid method, so that 

 the mitochondria (and nucleoli) become red, the Golgi apparatus 

 is black and the ground cytoplasm yellowish. The Mann-Kopsch 

 sections are brought down to distilled water, and cautiously 

 treated in a 0-5 to 0-125 per cent, solution of potassium permanga- 

 nate. They should be watched under the microscope. As soon 

 as the cytoplasm of the cells has become dark brown in colour, 

 and before any marked change in the impregnation of the Golgi 

 apparatus occurs, the slides are washed rapidly in distilled water, 

 and treated with sulphurous acid — about 5 to 10 per cent, solution. 

 This bleaches the cytoplasm almost instantly, while the Golgi 

 apparatus remains black. The slides should then be washed 

 thoroughly in running water and stained (§ 694). 



