CYTOLOGICAL M K'l'TlODS. 327 



freezing). The sections are stained either by iron lixmatoxijlin (twenty- 

 four hoiu-s in the mordant and in the stain, with differentiation in 

 Weigert's borax-ferricyanide), or by either of the two following methods : 



(a) The sections are oxidised for five minutes in O'o per cent, solution 

 of permanganate of potash, reduced in Pal's oxalic mixture till they 

 become white (about three minutes), dried with blotting-paper flooded 

 with WEiaBBT's methyl-violet-oxalic mixture, or with the crystal-violet 

 solution, § 330, dried, rinsed with solution of LtjgoI;, rinsed, dried again 

 with blotting paper, differentiated with a mixture of equal parts of 

 xylol and anilin oil, dried, rinsed with xylol, balsam. 



(b) Sections mordanted twenty-four hours in iron alum of 4 per cent. 

 or liquor ferri, § 241, diluted with 2 vols, of water, rinsed, stained twenty- 

 four hours in the sol. of sulphalizarinate of soda, § 653, rinsed, mopped 

 with blotting-paper, warmed in O'l per cent. sol. of toluidin blue till 

 vapour is given off, stained fifteen minutes more in the same solution 

 whilst cooling, dipped in acetic acid of 1 per cent., dried with blotting- 

 paper, dipped in alcohol, differentiated about ten minutes in beech- wood 

 creosote, dried with blotting-paper, rinsed many times with xylol, then 

 balsam. 



The Nehenkern of spermatic cells may be studied by the 

 methods indicated for centrosomes. Kemschwarz is also 

 very useful here. 



652. 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 gener- 

 ally employed stains are the mixtures of Bhelich. 



Litra vitam staining is useful here (see § 208). See also 

 Aenold, Anat. Anz., xxi, 1902, p. 417. 



Benua [Verh. phys. Ges. Berlin, 1899-1900, Nr. 1-4, and 

 Verh. Anat. Ges., xv, 1901, p. 172) gives the following 

 method for demonstrating secretion-granules and distinguish- 

 ing them from other granules : Harden for 24 hours in 10 

 per cent, formalin, then for one day in 0-25 per cent, 

 chromic acid, one in 0-33 per cent, and 2 to 8 in 0-5 per 

 cent., wash one day in water, dehydrate and make paraffin 

 sections. Then stain with one of BhrlicVs mixtures, accord- 

 ing as the granulations are basophilous, acidophilous, or 

 neutrophilous. The methylen-blue and eosin process of 

 Michaelis is recommended. 



For Prenant's Ergasto-plasm see especially Garniee, 



