MICROSCOPIC EXAMINATION 139 



should then be shaken and blown vigorously from the specimen 

 which is then dried rapidly in the air. As soon as it is thor- 

 oughly dry it may be examined using a two mm. (1/12 in.) 

 oil immersion objective. It is not necessary to place a cover- 

 glass on the specimen, as the index of refraction of homo- 

 geneous oil is the same as that of glass. If a dry objective 

 should be used a cover-glass would be necessary ; but as high 

 a magnification as that given by a two mm. (1/12 in.) objec- 

 tive is needed. The stained films keep as well without being 

 covered as when mounted in balsam. Immersion oil may be 

 removed from the film by dropping on chloroform or xylene. 



With Jenner's stain the red corpuscles should have a 

 pinkish or terra cotta tint; nuclei, blue; the fine granules of 

 polymorphonuclears, pinkish; eosinophile granules, deeply 

 stained pinkish; basophile granules, deeply stained dark vio- 

 let. Bacteria are well stained blue. 



Wright's stain. 7 The staining fluid may be obtained 

 ready for use from dealers in microscopical supplies. It is a 

 solution in pure methyl alcohol of eosinate of polychrome 

 methylene blue. The unfixed film which has dried in the air 

 is covered with the stain which is allowed to act one minute. 

 Then an equal number of drops of distilled water is added. 

 This is allowed to act two or three minutes longer when the 

 specimen is washed with distilled water until the better spread 

 portions have a pinkish or orange tint. A few seconds will 

 usually suffice, but it may take one to three minutes. The 

 excess of water is shaken and blown vigorously from the speci- 

 men which is then dried in the air. When it is dry examine 

 with the two mm. (1/12 in.) oil immersion objective. 



Wright's stain is excellent, staining the several kinds of 

 granules well. The red corpuscles should have a pinkish or 

 terra cotta tint; nuclei, blue; the fine granules of polymor- 

 phonuclears, pinkish ; eosinophile granules, reddish ; basophile 

 granules, a deep royal purple. This stain also stains bacteria 

 well. Wright's is preferable to Jenner's stain for staining the 

 protozoa found in the blood. 



7 Wright. Jour. Med. Research, Vol. VII (1902) p. 138. 



