44 PARASITIC AMOEBAE OF MAN. 



have been elaborated. Among the most important 

 are the following: 



Osmic Acid. This mixture consists of two parts 

 of osmic acid in 100 parts of a 1 per cent, chromic 

 acid solution, or a 4 per cent, solution of osmic acid to 

 which a certain amount of glacial acetic acid is added 

 at the time of fixation. ( 1 drop of glacial acetic acid 

 to 20 drops of the 4 per cent, solution of osmic acid.) 



It should be remembered that osmic acid is a 

 strong irritant of the mucous membranes and care 

 should be taken not to inhale the fumes or allow them 

 to come in contact with the eyes. The sealed tube 

 containing the acid should be broken in a glass stop- 

 pered bottle containing the desired amount of water 

 or other solution. 



Absolute Alcohol. When dry cover glass prepa- 

 rations are to be examined they may be fixed by 

 immersing them in absolute alcohol for from 2 to 5 

 minutes. 



Alcoholic Solution of Mercuric Chloride. The 

 mercuric chloride used in this mixture is obtained by 

 dissolving perchloride of mercury in boiling normal 

 saline solution in such proportions that a few crystals 

 of perchloride of mercury are deposited in the vessel 

 after boiling. In other words, a saturated solution 

 of perchloride of mercury in boiling saline solution 

 is to be obtained. 



