54 PRACTICAL PARASITOLOGY 



attachment of the head. If the head is now held by a pin at point h, 

 the two triple-lobed salivary glands (fig. 12, gl. sal.) may be removed 

 with a second pin from the loose connective tissue surrounding them 

 and, after severing the excretory ducts, they may be examined for 

 malaria parasites. This manipulation requires care and a little 

 practice. The anterior stomach (fig. 12, prov.) is prepared in a 

 similar fashion ; its folds may harbour numerous Hcemoproteus in 

 the Trypanosome stage, which will be found attached to the walls. 



For permanent preparations, the mid-gut should be slightly teazed 

 out upon a cover-glass and fixed as a cover-glass preparation in 

 alcoholic solution of mercuric chloride. Stain with hsematoxylin or 

 iron-hsematoxylin. The latter produces very pretty effects with the 

 older cysts of the malaria parasite, if the specimens are sufficiently 



FIG. 12. Diagrammatic illustration of the digestive and circulatory organs of a female 

 mosquito. The mouth-parts are omitted. (After Liihe, from Mense's Handb. d. Tropcn- 

 krankh). a, Aorta, c, Heart, cav. or., Oral cavity, col., Colon, g.i., Lower pharyngeal 

 ganglion, g.s., Upper pharyngeal ganglion, gl. sal., Left salivary gland (the excretory 

 duct only of the right salivary gland is shown), il., Ileum (commencement of mid-gut). 

 m., Mid-gut or stomach. CBS., (Esophagus, o.v., Venous orifices of the heart, p., Pharyn- 

 geal suction apparatus, prov., Anterior stomach (its folds may harbour numerous 

 Flagellates), r., Sphincter muscle (the proventricalus) at the junction of oesophagus and 

 mid-gut, rect., Rectum, with three papillae of the right side. s.L, Right dorso-lateral 

 diverticulum of the suction stomach (the left is cut away), s.-y., Ventral diverticulum 

 (invariably contains yeast-cells, which have sometimes been mistaken for developmental 

 stages of parasitic Protozoa), t.m., Malpighian tubes. 



decolorized for the parasites to show up darkly against the pale 

 grey colouring of the intestinal wall. Whole preparations of the 

 salivary glands are made in the same way. Sections may be cut 

 from the whole insect or from single organs fixed in alcoholic solution 

 of mercuric chloride. 



(5) EXAMINATION OF BLOOD. 



Blood for demonstration purposes should be drawn from the tail 

 artery of rats, mice and lizards, after cutting off the tip of the tail ; 



