i66 



Methods of Observing Micro-organisms 



• If the covers are to be stained, they can most conveniently be 

 held in the Stewart forceps. If the shdes are used, they can be 

 ■ held in the fingers. 



The stain most useful is that of Romanowsky. It has many 

 modifications, of which the most used and best known are Giemsa's, 



Fig. 2g. — Method of making dry film with two cover -glasses (from Daniels' 

 "Laboratory Studies in Tropical Medicine"). 



Jenner's, Leishman's, Wright's, and Marino's. These stains can 



be bought either in solution or in tablet form ready for solution. 



Those most highly to be recommended are Wright's and Marino's. 



Fig. 30. — Method of making dry films with two slides (from Daniels' "Labora-- 

 tory Studies in Tropical Medicine"). 



Wrighl's Blood-stain. — This is a modification of Leishmann's stain, to which 

 it is to be preferred because it can be made in a few hours instead of eleven 

 days. It combines the methylene-blue-eosin combination of Roman- 

 owsky with the methyl-alcohol fixation of Jenner. 

 It is prepared as follows:* 



"To a 0.5 per cent, aqueous solution of sodium bicarbonate add methylene- 

 blue (B. X. or "medicinally pure") in the proportion of i gm. of the dye 

 to 100 cc. of the solution. Heat the mixture in a steam sterilizer at 

 ioo°C. for one full hour, counting the time after the sterilizer has become 



* Mallory and Wright, "Pathological Technique," 191 1, p. 364. 



