390 BLOOD AND GLANDS. 



In some cases Goldmann has given fifteen consecutive injections. 

 These remarks refer especially to small animals like the rat ; for 

 bigger animals, such as the rabbit or ape, intraperitoneal injections 

 are preferable to subcutaneous : use the standard of 1 c.c. of a 

 1 per cent, solution per 20 grms. of animal's weight. 



min^blue and pjrroXJ^lue anow^of^fi^ation^in 

 solution (injected intravenously if possible), 

 but it is only tissues stained in trypan blue that allow ordinary 

 I processes of histological technique, but even for trypan-blue, the 

 'fixative should contain a little formalin. Sections are cut with a 

 freezing microtome from tissue fixed in 10 per cent, formalin not 

 less than forty-eight hours. Stain as necessary in alum carmine or 

 hsemalum, etc. Pappenheim's pyronin and methyl green are good 

 for connective tissues, Ehrlich's triacid for hsemopoetic tissues 

 (GOLDMANN, Proc. Roy. Soc.; Ixxxv, 1912), G. B. WISLOCKI and 

 H. DOWNEY (Anat. Record, xii, 1917), after staining, fix in Zenker or 

 formpl, upgrade in alcohols, imbed in wax and section. Counter- 

 stain in haemalum. GOLDMANN (loc. cit.) mentions the following 

 " vital stains," apart from those given above : Trypan violet, 

 benzopurpurin, diamin blue B.B., diamin black B.H., vital " neu 

 rot, vital neu orange," vital " neu gelb," dianil blue E, (Griibler). 

 These are used in 1 per cent, strength in salt solution. Trypan blue, 

 trypan red, Congo red, azo blue, and beiiz^purpurin can be used on 

 tissue cultures by introducing some of the dye into the culture 

 medium (SHIPLEY, Amer. Journ. PhysioL, 1919, p. 287). 



Apart from the references given above see also, HOFFMAN (Fol. Hcum., 

 1914.), KENAULT (Arch. d'Anat. Micr., 1907) ; LOELE (Fol. Hcem., 1913) ; 

 BATCHELOR (Proc. Amer. Assoc. Anat., 1914, Anat. Record, 1914). 



791. Mieroehemical Tests for the Oxygen Place in Tissues. Recently 

 certain workers have claimed to be able to locate centres or regions of 

 oxidation in the cell by means of some substances sensitive to free oxy- 

 gen. Unna's method is to use a solution of rongalit white, which is a 

 solution of the leucobase of methylen blue kept in a state of reduction 

 by excess of rongalit, an absorption product of formaldehyde with 

 sodium sulphite. See UNNA (Die ReduMonsorte und Satierstofforte des 

 tierscJien Gewebes, Arch. f. Mikr. Anat., Ixxviii, 1911). A. N. DRURY 

 (Proc. Roy. Soc., 1914) has shown that Unna's claim is inadmissible, 

 and consequently his theory of staining by oxidation and reduction is 

 not proven. GRAHAM (Journ. Med. Research, Boston, xxxv, 1916) 

 claims to have demonstrated by means of H 2 2 and naphthol, that the 

 granules of leucocytes and myelocytes contain a peroxidase of the 

 peroxide type. Schultze in his Oxydase Reaction uses a-naphthol and 

 dimethyl-p-phenylen-diamin (Merck). Blood and marrow smears fixed 

 in formalin vapour are treated firstly in the a-naphthol solution ; pre- 



