102 A MANUAL OF BACTERIOLOGY 



until the section becomes greenish. Pass through absolute alcohol, 

 clear, and mount. 



(12) Leishman's stain : 



Like the Jenner, Wright, and other similar ones, a modification 

 of the Romanowsky stain, a double compound of eosin and methyl - 

 ene blue. The solution will keep for some time, but is best freshly 

 prepared. Griibler's powder or Burroughs Wellcome 's soloid 

 may be used, and is dissolved in pure (Merck's or Kahlbaum's) 

 methyl alcohol. Failure frequently proceeds from the use of a 

 so-called pure methyl alcohol, which is not really so. (For method 

 of using, see " Malaria," Chapter XVIII.) 



(13) Giemsa stain: 



An eosin-azur mixture dissolved in pure glycerin and methyl 

 alcohol. Useful for blood-films, smears, etc., and has been much 

 used to demonstrate the spirochaetes in syphilitic material. (For 

 method of using, see " Syphilis " and "Malaria.") 



Safranin and acid fuchsin are also used as counter-stains. 

 Malachite green, neutral red, and rosein may be used for intra-vitam 

 staining of protozoa, etc. 



Eosin, orange-rubin, hsematoxylin, and picro-carmine keep well 

 in solution ; the remainder may or may not, and are best used 

 fairly fresh. All stains should be filtered before use, and may be 

 conveniently kept in bottles having a funnel fitted with a filter- 

 paper, so that they are always ready. Or smaller bottles may be 

 used, fitted with pipettes, and several arranged in a stand. 



Methylene-blue, Leishman and Giemsa preparations are more 

 permanent if kept unmounted. After examination with the oil- 

 immersion, the oil may be removed from the film with xylol. Coles 

 mounts these preparations in parolein. 



The best stains are Griibler's, which can be obtained from many 

 agents in this country. Messrs. Burroughs, Wellcome and Co. supply 

 most of the anilin dyes and some other reagents, iodine, etc., in 

 " soloids," which are very convenient and good. 



Gram's method. This is a most useful method, especially 

 for sections, specimens of blood, or films or impression 

 preparations, as the tissue or ground substance can be 

 counter- stained so that the organisms show up in marked 

 contrast. Ordinary films of cultures do not usually require 

 this method, unless debris or ground substance is present and 



