VARIETIES OF THE MALARIAL PARASITE. 523 



spring " fevers of Italian writers) were first distinguished by 

 Golgi. Their characters are the following : 



1. Quartan. The parasite passes through its cycle of 

 development in three days, and all the various stages are 

 found in the blood. Only the smaller forms within the 

 red corpuscles show amoeboid movements, and these are 

 not of very active character. The red corpuscles invaded 

 by the parasite do not become decolorised or altered in 

 size ; the pigment granules are somewhat coarse. Typical 

 rosette-forms are seen in the process of sporulation, which 

 results in the formation of six to twelve segments or spores. 

 The spores in the fresh blood show a central clear spot 

 which is not seen in the spores of the tertian parasite. 



2. Tertian The cycle of development of the parasite 

 is completed in forty-eight hours. The young forms within 

 the red corpuscles show much more active movement than 

 in the quartan type, and give off longer and more slender 

 processes, whilst the pigment granules are finer. The 

 infected corpuscles become swollen and pale. Sporulation, 

 resulting in the formation of from fifteen to twenty round 

 spores, takes place by means of a rosette or rather a 

 sunflower formation, the lines of segmentation being at 

 the periphery, and a portion remaining around the central 

 collection of pigment (vide Figs. 119-121). 



(1)} The more severe forms (aestivo-autumnal fevers). In 

 these the crescent forms are found (Fig. 123). 



i. Quotidian. This is the form most commonly 

 assumed by malarial fever in the tropics. The parasite 

 passes through its cycle of development in twenty-four 

 hours. Within the red corpuscles the parasite is of small 

 size, and even in its adult condition, immediately before 

 sporulation, does not usually occupy more than a third of 

 the corpuscle. The amoeboid forms often pass into the 

 " ring-form " described above. In their course of develop- 

 ment they acquire very fine dust-like pigment, and in the 

 adult quiescent form the pigment becomes collected into 

 a small dark body. The spores (usually six to eight) are 

 formed by irregular segmentation, and are very minute ; the 



