OTHEK NUCLEAE STAINS BY THE INDIRECT METHOD. 65 



PODWYSSOZKI (1. c.) gives another method, which consists in 

 washing out (for from a few seconds to two minutes) in a 

 strongly alcoholic solution of picric acid followed by pure 

 alcohol. Same results (except that the stain will be brownish 

 instead of pure red). 



BABES employed for washing out after staining in the 

 aqueous or alcoholic solutions above mentioned, pure alcohol 

 followed by oil of turpentine. For sections stained in the 

 anilin solution he recommends treatment with iodine according 

 to the method of Gram (see what is said as to the process of 

 Gram in the paragraph on gentian violet, ante, 102). This 

 process has also been recommended by PEENANT (Int. Monats- 

 schr.f. Anat.j &c., iv, 1887, p. 358), who notes that the treat- 

 ment with the iodine solution should be somewhat longer, and 

 the treatment with alcohol somewhat shorter than with gentian 

 violet sections. 



MAKTINOTTI and EESEGOTTI (Zeit. f. wiss. Mik., iv, 3, 1887, 

 p. 328) recommend washing out with a freshly prepared mix- 

 ture of one part of 0*1 per cent, aqueous solution of chromic 

 acid with nine parts of absolute alcohol, followed by pure 

 alcohol and bergamot oil. In my experience this method does 

 not give better results (I think less good) than that of washing- 

 out in the simple aqueous solution of chromic acid of Bizzozero 

 followed by alcohol (see the paragraph on gentian violet, ante, 

 102). The latter is certainly a most useful method. It 

 should be mentioned that Martinotti and Resegotti's results 

 refer to lightly stained alcohol-fixed objects, and not to chromo- 

 aceto-osmic objects, which may make a great difference. 



GARBINI (Zeit. f. wiss. Mik., v. 2, 1888, p. 170) has recom- 

 mended that sections be dehydrated after staining in methylic 

 alcohol (wood spirit) in which safranin is only very slightly 

 soluble, and decoloured in a mixture of two parts of clove oil 

 with one part of cedar oil. I have not been able to obtain 

 good results by this method. 



The reader will remember that safranin may be washed out by substitu- 

 tion (see ante, 98). In preparations made with chronio-aceto-osmic acid, 

 sa f'ran in stains, besides nuclei, elastic fibres, the cell-bodies of certain horny 

 epithelia, and the contents of certain gland-cells. 



104. Other Nuclear Stains by the Indirect Method. The fore- 

 going paragraphs nearly exhaust the list of colours giving good nuclear 



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