372 RESEARCH IN PROTOZOOLOGY 



except in those in more advanced stages. The pigment varies 

 somewhat with the species of malaria parasite, but always appears 

 as a clump or chain of granules varying in color from brown to 

 almost black. They appear in sharp contrast when the diaphragm 

 of the substage condenser of the microscope is opened widely. 



.Sometimes fat droplets or immature ova underlie or overlie a 

 flattened stomach and may simulate oocysts. These will not be 

 attached to the gut and may often be removed by alternately lift- 

 ing and lowering the coverglass, a new drop of salt solution hav- 

 ing been added at its margin. Or the coverglass may be moved 

 laterally by means of a needle, preferably under microscopic con- 

 trol, thus rolling the stomach until the doubtful body appears at 

 the side. It is usually possible to identify oocysts on the flattened 

 surface of the stomach without rolling it. 



Dissection of salivary glands. The salivary glands are found in 

 the upper part of the thorax a little below the neck. A method in 

 common use for dissecting out the glands is as follows: Remove 

 the legs and wings of the mosquito and place it in a drop of salt 

 solution. Hold the thorax with one needle, place the other between 

 the head and thorax and with it draw the head slowly from the 

 body. The glands often come out attached to the head and may 

 be cut away from it with the needle. If they do not come out, they 

 may be pressed or dissected out from the portion of the thorax 

 in which they lie. 



I have devised a technique which ofifers some advantages. Re- 

 move the legs of the mosquito and cut ofif the head cleanly from 

 the body. The wings need not be removed, especially if they pro- 

 ject backward. These operations can be quickly done on the slide 

 by means of needles with points ground to sharp blades. Place 

 the specimen on its side in a very little salt solution with the thorax 

 to the right of the observer. By means of a pair of fine forceps 

 held in the right hand pick up a small square cover, about five 

 millimeters square, and slope it on the thorax (Fig. 23). Keep 

 the mosquito in position with a needle held in the left hand. Press 

 down the cover with the forceps in such a way as to squeeze out 

 the contents of the thorax situated just below the neck. As the 

 coverglass descends withdraw the thorax by means of the needle 

 held in the left hand. 



The glands almost always come out and are found well under 

 the coverglass. They usually appear in a single group. If they are 



