AND ZTGOTES IN MOSQUITOS INFECTED WITH MALARIA. 3 



Dc not food the slide with salt solution as the glands when extracted may float 

 away and be lost. Reniemher that the ji'lands lie jnst at the point of ovig-in of 

 the first pair of legs. 



(6.) Place the slide upon a piece of ivhiie paper, as you are dissecting a dark 

 object. Take a needle (in a holder if convenient) in each hand, holding them 

 nearly horizontal. Place the left needle 07i the thorax so as to steady it and the 

 rif/hf needle at the back of the head (fig. 1), and now make a series of gentle, slow, 

 " coaxing " pulls on the head with the right needle, taking about ^-^ a minute 

 over it. 



(c.) If this has been done carefully (and anyone with the least delicacy of 

 touch can succeed 99 times out of 100), a bit of white tissue is now seen attached 

 to the head. This contains the glands. 



(d.) Examine under about ^-inch lens, remembering nearly to close the diaphragm 

 as an unstained object is being examined. The glands are glistening, finger-like 

 and a little twisted, and project from the end of the head, or possibly only their 

 tips may be seen in the midst of some grey muscle or " fat body." 



(e.) Separation from head : — Put the left needle on the head and with the right 

 3ut or tear off the white tissue containing the glands. (N.B. — Take care that hy 

 this time the salt solution has not dried or that the (/lands have not stuck to the 

 needle.) 



Examination of the Glands. 



(a.) The glands are generally quite free when dissected in this way, but even 

 if still attached to a bit of tissue it is quite unnecessary to separate them any 

 further. It is not necessary that all six lobes should be present, three may be 

 considered suflficient (fig. 2). Note the exact position on the slide with a low 

 power. 



Fig. 2. — The salivary glands of one side. 



(6.) If the salt solution has become turbid carefully draw the glands into a 

 fresh drop of solution on the slide, remembering that apparent right and left under 

 the microscope are actual left and right on the slide. 



(c.) Drop a cover-glass over them. 



{d.) Examine with a ,1 or | inch lens. An oil immersion is unnecessary for 

 detection of sporozoits as they are in length about twice the diameter of a red 

 ceU. 



