174 BACTERIOLOGICAL DIAGNOSIS. 



show amoeboid movements of greater or less rapidity. 

 When the parasites are older they occupy a larger 

 space in the corpuscles, and there are granules of dark 

 pigment around their periphery. These granules are 

 often the first indications of the presence of parasites in 

 the examination of an unstained specimen. At a still 

 later stage the granules will be found in the centre of 

 the corpuscle (the haemoglobin of which is now almost 

 entirely removed), and the parasite will show segmen- 

 tation into a larger or smaller number of spores by lines 

 which have a radial arrangement and give the whole 



FIG. 29. Malarial parasites in the blood. The dark area shows the 

 parasite as it appears when stained with thionin. 



an appearance resembling that of a marguerite daisy. 

 These are only found when a rigor is imminent. 



Crescents are found in the aestivo-autumnal form 

 of malaria ; they are crescentic bodies with rounded 

 " horns," and contain a ring of pigment granules in the 

 centre. They cannot be mistaken for anything else, 

 and if a single one is found it affords conclusive proof 

 that the patient has been infected with malaria. 



Films for staining are made in the ways already 

 described, and must be thin and perfect. They may be 

 fixed by any of the methods we have recommended, the 

 alcohol-ether and the alcohol-formalin methods being 

 perhaps the best. They may be stained by Jenner's 



