VITAL STAINING 343 



Chlopin has called the Krinom. It can be demonstrated by 

 fixation in Helly's fluid (Zenker-formol) and countcrstaining with 

 thionine or eosin-azure. With the latter staining it appears blue 

 against the pink background of the cytoplasm. 



LuDFORD {Proc. R. S. B., cviii, 1931, p, 270) has demonstrated 

 the same formations by fixation in Champy's fluid, bleaching 

 section in hydrogen peroxide (1 part of HgOg to 4 parts of 80 per 

 cent, alcohol), and then counterstaining with acidulated neutral 

 red (see § 748). 



769. Other Basic Dyes for Staining Cytoplasmic Vacuoles and 

 Granules. Other dyes which may be employed, and stain 

 similarly to neutral red, are neutral violet, brilliant cresyl blue, 

 Nile blue sulphate, Bismarck brown, Nile blue chlorhydrate, 

 toluidine blue and thionine. They can be applied to cells in the 

 same way as neutral red. 



770. The Staining of Fat Droplets. Fat can be stained by 

 feeding animals with food to which a fat soluble dye, such as 

 Sudan III., or scarlet R. has been added. The dye may be 

 dissolved in olive oil, and this mixed with dry food, or the dye can 

 be well mixed with fatty foodstuffs. Solutions in alcohol and 

 acetone have been injected directly into animals (see Hadjioloff 

 and OizouNOFF, Compt. rendus, cxiii, 1933, p. 1501). Ludford 

 (11//? Sci. Rep. Imp. Cancer Res. Fd.. 1934, p. 169) has devised a 

 method of vitally staining fat by employing " solutions " of Sudan 

 III. and Sudan black in serum. The method of preparation is as 

 follows : A small quantity of the dye is added to freshly-prepared 

 serum contained in a small test-tube, provided with a tight-fitting 

 rubber stopper in order to prevent loss of COg. The test-tube is 

 vigorously shaken from time to time and kept in a warm place. 

 Within twenty-four to forty-eight hours the serum becomes 

 coloured. It is then centrifuged and the coloured transparent 

 fluid pipetted off. This is relatively stable, and can be used for 

 intra-vitam or supravital staining, or for staining cells in tissue 

 cultures. 



The basic dyestuff Nile blue which is soluble in water, as well 

 as in lipoid solvents, has also found employment for the staining 

 of fatty compounds. According to the recent work of Lison {Bull. 

 d'Hist., X, 1933, p. 237 ; ibid., xii, 1935, p. 279) the blue staining 

 with this dye is of no histochemical significance, but the rose 

 coloration signifies the presence of an unsaturated glyceride 

 (trioleine). It is not possible to distinguish between different 

 classes of fatty compounds by vital staining. 



PART IV. SPECIAL METHODS 



771. Vital Staining with Leucobases. Roskin and his collaborators 

 (RosKiN and Semexoff, Zeii. f. Zellforsch., xix, 1933, p. 150 ; 

 RosKix and Maslowa, Zeit. f. wiss. Mikros., lii, 1935, p. 309), 



