6io LABORATORY HINTS 



The finding of crescents establishes the diagnosis. 



A sporulating subtertian fills about one-third of the red cell. 



A sporulating quartan fills the cell. 



The crescents or subterlian gametoc^^tes are especially interesting. 



The sexes are differentiated. They do not produce fever, 'i'hey 

 undergo no change in man's blood. The}^ appear one week after the 

 fever has commenced and persist for six \\eeks after quinine has been 

 given. Although the patient has no fever, he is infective as long as 

 these crescents remain in the blood. 



In the quartan parasites the red cells are never enlarged. The 

 affected cell is darker than the normal ones, it requires longer to 

 develop, seventy-two hours; it has fewer spores, five to twelve, than 

 benign tertian, but they are the largest of all. Sporulates in the peri- 

 pheral blood. Corpuscle becomes smaller and darker. Gamete 

 rounded, the pigment is black, and granules coarse. There is little 

 amoeboid movement. The parasite may be stretched out across the 

 cell "cigar-shaped," when it is called an "equatorial " parasite;. 



The pigment of the male dances about, throws off flagella which 

 are very active. In ten to fifteen minutes they break off and swim 

 freely in the blood until they pierce a female cell. The female cell is 

 quiescent after the polar bodies have been extruded. The fertilized 

 female or zygote becomes oval " ookinet," and later when it moves 

 it is known as a travelling vermicule. The leucocvtes gather around 

 the male cell when the flagella have been thrown off and remove them. 

 This process can be seen under the microscope in specimens of fresh 

 blood. 



TO EXAMINE FRESH BLOOD FOR MICROFILARIAE. 



Make a thick film of several drops of blood and let it dry. 

 Place it inverted in a watch-glass of water so as to remove hb. 

 from the blood. 



Fix it in alcohol and ether. 



Stain ^\•ith hot hc'ematoxylin five minutes, then flush with water. 



Examine while wet. Repeat stain if not well blue. 



Dry and mount. 



THE WASSERMANN REACTION (FLEMING'S MODIFICATION). 



This important diagnostic reaction of the blood depends upon the 

 l^rinciple of hiemolwsis. If the case for diagnosis be really a case of 

 syphilis, then no hasmolvsis will occur. A control experiment is 

 carried out at ihe same time, using normal serum. 

 The substances required are: — - 



(i) An alcoholic extract of heart muscle. It is made from i grm. 

 of heart muscle (guinea-pig) rubbed in a mortar with 25 c.c. 

 absolute alcohol, heated to 60° C. for an hour and filtered. 



