PLASMODIUM PR^ECOX 527 



Haematoxylin (Ehrlich's, or Mayer's haemalum) is preferable for 

 permanent preparations, and in hot countries, where methylene- 

 blue rapidly fades. The preparations may be counter-stained with 

 a weak solution of eosin. 



Ross recommends for rapid diagnosis the use of thick blood films, 

 from which the haemoglobin is first removed with very dilute acetic 

 acid ; the films are then stained with Leishman's stain, and 

 examined with a J-inch objective. Practice is required for this 

 method. 



In order to demonstrate the flagellated organisms Manson 

 recommends the following procedure : Thirty or forty strips of 

 thick blotting-paper (3 inches by 1J inch), each having an oblong 

 hole (^ inch by f inch) cut lengthways in the centre, are prepared, 

 moistened with water, and laid on a sheet of window glass. A 

 patient 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 inch by inch. 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 simi- 

 larly 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 haemo- 

 globin. 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 commencement 

 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. 



[For further particulars on Malaria and on the demonstration of 

 the malaria parasite, see Daniels' Laboratory Studies in Tropical 

 Medicine, 1908.] 



