FORMS OF MALARIAL FEVER 375 



subdivisions, and clinical nomenclature have passed through a variety 

 of changes. The three old divisions have been retained here for 

 convenience. Sir Patrick Manson has suggested the following 

 classification : 



4 TJ f Quartan 1 In which the parasites do 



A. Benign . ^J ertian ) = not form crescents. 



( Quotidian with pigmentation ^ In which the para- 



B. Malignant -I Quotidian without pigmentation j- = sites do form 



( Sub-tertian ) crescents. 



Now in some forms of malarial fever, namely, the malignant 

 infections, the spherical bodies or mature form immediately prior to 

 segmentation into rosette bodies, do not actually show segmentation, 

 but assume the form of crescents lying inside the blood corpuscle, the 

 haemoglobin of which has been absorbed. Between the poles of the 

 crescent may be seen the membrane of the blood corpuscle, the 

 crescent being folded somewhat on itself. These crescents represent 

 the form of the parasite which requires to enter the body of the 

 mosquito in order to attain development. The crescents do not, as 

 a rule, appear in the blood until about one week from the onset of 

 the fever, and are the first stage of the extra-corporeal phase of the 

 parasite. They are termed the gametocytes, and are of two kinds, 

 male and female. It will be necessary to follow the development of 

 each kind separately. 



The mierog'ametoeyte, or male gamete, is the parasite in crescent 

 form, with the delicate membrane of the containing blood corpuscle 

 at first investing it, as described above. These crescents are hyaline 

 in appearance, and the motionless pigment is loosely arranged. The 

 crescent eventually absorbs or exhausts the blood corpuscle, and 

 becomes a free body in the blood serum. Next, it changes by 

 becoming kidney-shaped, then round at the poles, thicker, more 

 ellipsoidal, and eventually spherical. The pigment granules now 

 become mobile, and eventually assume most active movement and 

 become diffused throughout the whole sphere, and almost immedi- 

 ately thereafter the sphere itself becomes agitated, and from* its 

 circumference shoot out long flagella (microgametes). This flagellated 

 parasite is a weird -looking, " octopus-like " body, with long lashing 

 tentacle-like flagella, and containing in its centre a mass of moving 

 pigment granules. The flagella or microgametes are of the nature 

 of spermatozoa, and fulfil a similar function, and are in length some 

 three or four times the diameter of the microgametocyte. They are 

 unpigmented, and may bear at their extremities bulbous swellings. 

 They break off and become free in the blood, continuing their 

 active movements. 



The flagellated body may be produced from free spheres of the 



