LABORATORY METHODS IN MALARIA 373 



mixed with more opaque material from the thorax, they may be 

 washed free by Hfting the left side of the cover at which a little 

 salt solution alone is sufficient to hold the coverglass in position 

 intact, the coverglass should not be pressed down closely; but 



Fig. 23. — Position of mosquito, coverglass, forceps and needle in the process 

 of pressing out the salivary glands. 



sporozoites may be easily recognized when partially pressed out 

 from the glands. 



It is more convenient to remove the salivary glands while the 

 abdomen is attached, but it is quite possible to press them out 

 after the removal of the abdomen for the dissection of the stom- 

 ach. 



The whole process is made a little easier if the coverglass is 

 first set up at an angle on the slide and held in position by a very 

 small amount of stiff balsam. Then the coverglass may be pressed 

 down with a needle after the thorax is in place, the balsam acting 

 as a hinge. The use of balsam, however, is hardly necessary. The 

 salt solution alone is sufficient to hold the coverglass in position 

 when it is sloped on the thorax ; one may then release the grip of 

 the forceps on the margins of the cover and press it down with 

 a tip of the forceps or with a needle. 



Sporozoites are usually recognizable by their form and their 

 position in the salivary glands, but it is always advisable to con- 

 firm the diagnosis by the use of some Romanowsky stain, which 

 colors the chromatin of the sporozoites red and the cytoplasm 

 blue or violet. In preparing the preparation for staining, the cover- 

 glass may be lifted and placed, wet side up, over a very small 



