118 SUMMARY OF CURRENT RESEARCHES RELATING TO 



procedure is successful : (1) Fix in Ciaccio's fluid ; (2) bichromate 

 lor about a week ; (3) Marchi's fluid for 24 to 48 hours, followed by 

 bichromate for 48 hours ; (4) the rest of the procedure is as before. 

 By the first method, ordinary fats are dissolved, while the lipoids 

 (myelin sheath, adrenal, etc.), are picked out in orange-red by 

 Sudan iii. By the second method it is occasionally possible to demon- 

 strate the co-existence of fat and lipoid in the same cells, a black centre 

 with a red or brownish-red margin or halo. 



Modification of Gram's Method of Staining.* — S. Stephan de- 

 scribes a modification of the Gram procedure, which is specially useful 

 for staining sections. The alcohol-fixed sections are stained in carbol- 

 water-methyl-violet 6 B solution for 10 minutes to 1 hour or more. 

 .On removal they are washed in water, and then immersed in the 

 following mixture, freshly prepared before use : 10 p.c. ferricyanide of 

 potash 1, and 5 p.c. potassium iodide, for 10 minutes. After washing 

 in water, the sections are thoroughly decolorised in absolute alcohol. 

 They may now be contrast -stained with dilute carbol-fuchsin or eosin, 

 and afterwards mounted in balsam. 



Staining- Eosinophil ous Cells.f— L. Martinotti finds that absolute 

 methyl-alcohol is the best fixative for smears, and that ether-alcohol 

 (equal parts) and heat are also very good for the purpose. For fixing 

 pieces the best fluids are sublimate, formalin, and methyl-alcohol. The 

 author's formula for sublimate is as follows :— Sublimate, 21 grm. ; 

 alcohol, 95-100 p.c, 150 c.cm. ; physiological saline, 279 c.cm. ; acetic- 

 acid, 150 c.cm. For staining the granules in sections some of theeosins 

 must be used, and from these are picked out the bluish-eosin, the pure 

 French-eosin, and the extra-eosin Hochst, all obtained from Griibler. 

 The preparations may be contrast-stained with methyl-eosin, safranin, or 

 cochineal. For staining the granules on smears the eosin-methylen-blue - 

 mixture of Jenner and of May-Griinwald are recommended. A copious 

 bibliography is appended. 



(6) Miscellaneous. 



Bum's Indian-ink Method.}— A. A. Gins finds that this method 

 is very satisfactory for demonstrating micro-organisms, blood-plates, etc. 

 A film is made of a mixture of the ink and the material to be examined 

 just after the manner of a blood-smear. The method is also adapted 

 for enumerating bacteria in a suspension. Eight photographs show 

 organisms clearly depicted on a dark ground. The ink-smears may be 

 after-stained, e.g. with Giemsa's solution. For making the films a 

 smearer like Wright's is used; the author described the' procedure for 

 making a smearer out of a slide. 



* Centralbl. Bakt. lte Abt. Orig., li. (1909) pp. 94-6. 



t Zeitschr. wiss. Mikrosk., xxvi. (1909) pp. 4-28. 



t Centralbl. Bakt., lte Abt. Orig., Iii. (1909) pp. 620-5 (4 pis ) 



