CYTOLOGICAL METHODS. 365 



extracted in the iron alum until the chromatin has become 

 entirely or almost entirely colourless. Instead of Bordeaux, 

 "anilin blue " may be used in the same way. 



See also Ehrlich's triacid, 291, and his acidophiloiis 

 mixture, 309 ; also Wasserblau, 312, and other reagents 

 mentioned in Chap. XVI. 



Also Gold Chloride, Apathy's process, 358. 



HERMANN (Arch. /. mik. Anat., xxxvii, 4, 1891, p. 583) recommends a 

 modification of the haematoxylin impregnation method of PAL, for which 

 see previous editions ; also his paper, " Methoden zum Studium des Archo- 

 plasmas und der Centrosomen tierischer und pflanzlicher Zellen," in 

 Ergebnisse der Anatomie, Band ii, 1892 (1893), p. 23. 



For HEIDENHAIN'S Vanadium hsernatoxylin, see COHN in Anat. Hefie, 

 1895, p. 302, or Zeit.f. wiss. Mile., xii, 3, 1896, p. 359. 



651. Cell Granules. For the study of the conspicuous 

 "granules/" undoubtedly metabolic products, occurring in 

 certain gland-cells and blood- and lymph- corpuscles, and in 

 certain elements belonging to the group of connective tissues, 

 see the sections on " Connective Tissues." The most generally 

 employed stains are the mixtures of Ehrlich. 



For ALTMANN'S " Bioblasts " see previous editions, also the critique of 

 FISCHER, in his Fixirung, Fdrbung, und Ban des Protoplasmus, pp. 108, 

 295. 



652. Nucleoli are " acidophilous " in so far as, in fixed 

 material, they select the acid dye or dyes from mixtures such 

 as the Ehrlich-Biondi stain. With this they stain mostly 

 red, sometimes orange. With fresh material they do not 

 stain at all with acid methyl green (distinction from 

 chromatin). 



But in fixed material treated with basic dyes (safranin, 

 gentian, etc.) by the regressive method they stain more 

 energetically than resting chromatin, and at least as much 

 so as chromatin in the kinetic state. With iron-haematoxylin 

 they stain sometimes full black, sometimes grey with a black 

 shell. 



They can frequently be well demonstrated in unstained 

 preparations examined in water, being brought out by their 

 superior refractivity. 



