26 SEVENTEENTH REPORT. 



B. Methylene blue. 



Methylene blue 1 gni. 



Distilled water 50 cc. 



Glycerine 50 cc. 



C. Eosin. 



Eosin water-soluble 1 gm. 



Distilled water 100 cc. 



All of the above should be kept in lightly stoppered bottles and 

 away from strong light. 



The amount of each one necessary has to be tried out in order 

 to determine what proportion will give the stain desired. It will 

 depend somewhat upon the depth of the color in the polychrome. 

 Distilled water 15 cc. or 15 cc. or 15 cc. 



A 9 drops 10 drops drops 



B 7 " 8 '' 6 '• 



C 2 " 3 " 1 '• 



A metallic sheen should api>ear on top of the mixture. 



Too much eosin will make the organism too pinkish. 



Method of staming: A thin smear is made on either the slide or 

 cover slip. This is air-dried and fixed in alcohol and ether (equal 

 parts) for 5 minutes. The fixing solution is rinsed off with taj)- 

 water. The preparation is put into the staining mixture either in 

 a watch glass or in a s^taining dish (large enough for one slide) 

 with the smeared side down and the end of the slide resting on 

 the edge of the dish, or with the cover slip floating on the stain. 



After the slide or cover slip has been in the staiu for 15 or 20 

 minutes, it is washed and examined. If it is not stained heavy 

 enough, the preparation is resitained, but a fresh solution is used. 

 The old one cannot be used the second time, the necessary staining 

 ingredients have been used up in the first operation, v^ometimes a 

 third staining has to be made". Each time a new solution must be 

 used. The depth of color is not improved by being kei>t in the stain 

 over 25 minutes. 



The protoplasm of the soil protozoa stains a blue, the nucleus 

 red, and the food vacuole with its food particle a deep blue. Many 

 of the other vacuoles appear clear; that is, do not show any color. 



According to (Jiemsa\ the red stain of the nucleus is due both to 

 the methylene azure of the polychrome and to the eosin, while 

 Michael is- and ^McXeaP claim that it is due to the azure alone, 



1. O. (Memsa, Farbeu Mcthodcn filr Malaria Parasiten, Cent. f. Bakt. 1902, I Abt. 

 32, p. 307. 



2. L. Micliaclls, Das Motlivlcuc Blau \ind Seine Zersetzung Product. Cent. f. 

 Bakt, l!t01, I Abt.. 29, p. 703. " 



3. W. McNoiil, Metlivloue Violet nm\ Motlivlcuc Azure, Jourii. of Infect. Dis., 1906, 

 3, p. 432. 



