544 NEUROGLIA AND SENSE ORGANS 



stained in various shades of blue and greyish-blue ; all other elements 

 yellowish-grey or yellowish-brown. 



Ranke (Ztscfir. ges. Neurol, xi. Psych., vii, 1911, p. 355) uses for 

 similar purposes either celloidin sections of foetal tissues fixed in picric 

 acid alcohol or sections made by freezing from formalin (pathological) 

 material. In the first case the sections are stuck to slides by pressing 

 with filter paper and then pouring on them methyl alcohol imtil all 

 celloidin is dissolved. He next stains them for a few minutes with his 

 acid eosin-thionin solution (see further on), washes with water, and re- 

 stains them, with the help of gentle heat, with 5 : 1000 Giemsa's 

 " Methylenazur I " ; quick differentiation with distilled water ; 96 per 

 cent, alcohol, cajeput oil, xylol, balsam. In the case of pathological 

 material the sections are first treated with 1 per cent, osmic acid in 

 order to stain fatty products of degeneration, etc., then pressed on to 

 slides and stained as above. To prepare the acid eosin-thionin mixture, 

 mix and shake repeatedly 1000 c.c. of each 1 : 1000 watery solution of 

 eosin W.G. and 1 : 1000 watery solution of thionin. Leave for forty- 

 eight hours, pour out the fluid part, and wash the sediment into a paper 

 filter with distilled water until the wash-water is only a little stained. 

 Dry what remains in the filter, and dissolve it in methyl alcohol in the 

 proportion of 0-3 to 0-5 per cent. 



1091. Alzheimer's Methods (Histol. u. Histopathol. Arh, iii, 

 1910, p. 406) :— 



{a) " Alzheimer-Mallory " Method. Fix in gliabeize + 10 

 per cent, formalin, wash and cut frozen sections. Wash rapidly 

 first with distilled water and then for two minutes with distilled 

 water rendered very slightly acid with acetic acid. From this 

 put directly into the stain which consists of 10 c.c. 10 per cent, 

 phosphomolybdic acid, 1-75 grm. of haematoxylin, 5 grm. phenol 

 crystals, and 200 c.c. distilled w^ater (ripened for two months), 

 wash, dehydrate, clear and mount in balsam. (Specially suitable 

 for demonstration of cell bodies and certain granules.) 



Weil {loc. cit.) stains paraffin sections in the hiematoxylin for 

 half to one hour after treating them for five minutes with 5 per 

 cent, potassium bichromate. He advises thorough washing with 

 50 per cent, alcohol before further dehydration. 



(6) " Alzheimer-Mann " Method. Fix in gliabeize + 10 per 

 cent, formol. Cut thin frozen sections and transfer first for ten 

 minutes to distilled water to which a few drops of 10 per cent, 

 phosphomolybdic acid are added, and then for several hours to 

 a saturated watery solution of phosphomolybdic acid. Wash 

 twice rapidly in distilled water and stain for one hour in Mann's 

 methyl blue eosin solution (1 per cent, methyl blue 35 c.c, 1 per 

 cent, watery eosin 35 c.c, distilled water 100 c.c). Wash in 

 distilled water till no more stain is given off, transfer for one to 

 two minutes to 96 per cent, alcohol, then absolute alcohol, xylol- 

 balsam. This method may be used on paraffin sections, fixing 

 material in 25 jDcr cent, formalin and subsequently mordanting in 

 5 per cent, potassium bichromate for fourteen days before im- 

 bedding in paraffin. 



