774 THE ELEMATOZOON OF MALARIA 



Wash rapidly (for a few seconds) in distilled water. Dry. The preparation may 

 be examined and preserved at this stage or may be mounted in balsam. The colour 

 reactions are the same as with Irishman's stain. 



Giemsa 's stain. This method is based upon the use of a mixture of solutions 



of azur II and eosin, and has been described at p. 727. Laveran modified 



the technique somewhat to make it applicable to the staining of Hsematozoa. 



The dried blood film is fixed in absolute alcohol and then stained for 10 minutes in 



the following solution : 



0-1 per cent, aqueous solution of eosin, - - 2 c.c. 



Distilled water, - 8 



0-1 per cent, aqueous solution of azur II, - 1 



Wash in water, treat for 2 minutes with a 5 per cent, aqueous solution of tannin. 

 Wash, dry and mount. 



Marino's stain. This method, which has already been described at p. 727, 

 may be used to stain the Hsematozoa. It is based upon the use of a mixture 

 of eosin, methylene blue and azur. 



Morphology. 

 Appearance in human blood. 



In the blood of persons infected with malaria the hsematozoon assumes one. 

 of the following forms. 



1. The mtra-corpuscular amoeboid form (Spherical body) [Ring parasite]. 

 The amoeboid trophozoites within the red cells are the forms most commonly 

 seen. They are small spherical structures 1 G/A in diameter, composed of an 

 hyaline, colourless, transparent protoplasm, and since they exhibit amoeboid 

 movements are sometimes known as the amoeboid bodies. As a rule they 

 appear like small clear specks attached to the red cells. 1 Two, three and 

 even four parasites may be present in one red cell. Occasionally they are 

 found free in the serum. 



Even the smallest of the amoeboid bodies sometimes contain one or two 



grains of black pigment (melanin), and as the 

 parasite increases in size pigment becomes 

 more abundant. The pigment grains are 

 sometimes arranged like a wreath around 

 the margin of the amoeboid body and at 

 other times dotted irregularly through the 

 substance : they often show active move- 

 ment which is more irregular and less 

 constant than Brownian movement. 



The amoeboid bodies have in addition a 

 nucleus, situated excentrically, attached to 

 the periphery, and difficult to stain. In 



preparations stained with methylene blue, 

 FIG. 371. The malarial parasite In S. i r J.T. -. i 



human blood, x looo. a, The young tne protoplasm of the parasite is coloured 



SS^SPSTuS am < Eboid ' or P ara - blue while the nucleus is represented by a 

 site; b, at a later stage; c and d, stages , , ^ . . , , , J , 



in the segmentation of the schizont; e, clear vacuole. Stained by Komanowsky s 



S Z lDLg?ammaticT segmenting schi ' or Laveran's method a chromatin granule 



within the nucleus is stained violet. 



In fresh blood films, at the end of half to three-quarters of an hour the 

 amo3boid movements cease and the parasite dies ; the margins then become 

 irregular and the grains of melanin accumulate irregularly in various parts 

 of the parasite. 



1 [This is now considered to be merely an appearance. The parasites are believed to- 

 be always within the red cells. ] 



