652 A MANUAL OF BACTERIOLOGY 



is selected in whose blood the crescentic form is plentiful, and a 

 minute droplet of the blood, about the size of a pin's head, is 

 expressed from a prick. A clean slide is then breathed on, and 

 the droplet of blood picked up on it and spread out with a needle 

 so as to cover an area f in. by in. The slide is immediately 

 inverted over a blotting-paper cell and pressed down sufficiently 

 to secure perfect apposition. The rest of the paper cells are 

 similarly covered with blood-charged slides. In from half to 

 three-quarters of an hour the slides are removed and dried by 

 gentle warming, and then fixed with absolute alcohol for five 

 minutes. The alcohol is allowed to evaporate, and the films are 

 treated with a few drops of 15 per cent, acetic acid to dissolve 

 out the haemoglobin. The slides are then washed in water and 

 stained with weak carbol fuchsin (20 per cent.) for six to eight 

 hours, washed in water, dried, and mounted. 



N.B. Negative results in the examination for the malaria 

 parasite must be accepted with caution unless repeated. A single 

 undoubted parasite is sufficient to establish the diagnosis. Quinine 

 causes the disappearance of the parasite. The parasites in the 

 sub-tertian fever disappear during the apyrexial intervals (except 

 the crescents), and are most likely to be found at the commence- 

 ment of the attack i.e. when the temperature is rising. The 

 parasites of the other forms are larger and more obvious during 

 the apyrexial intervals. 



Plasmodium praecox 



Syn. Proteosma Grassii, Hcemamceba relicta. 



This parasite (commonly called " proteosoma ") is met with 

 in sparrows and other birds, in which it invades the red blood - 

 corpuscles, and its structure and development are practically 

 identical with those of the benign malarial parasites of man. It 

 grows from a minute granule into an amoeboid plasmodium, 

 which ultimately segments and forms a rosette. In some speci- 

 mens of blood flagellated male gametocytes make their appear- 

 ance, similar to those of malaria, the flagella break away from 

 the main mass, fertilise other non-flagellated or female cells, 

 and a series of changes ensues analogous to those occurring in 

 the malaria parasite (p. 640). The fertilisation and development 

 of the fertilised cell take place in the stomach of a mosquito 



