638 A MANUAL OF BACTERIOLOGY 



bula, contains a vesicular nucleus and a nucleolus, and 

 the melanin granules are present in the surrounding proto- 

 plasm. When segmentation occurs, each segment con- 

 tains a portion of both the nucleolus and the protoplasm. 

 The maturation of each " brood " of parasites is coin- 

 cident with a fresh febrile paroxysm. 



In the sub tertian (pernicious) form of malarial fever 

 there exist in the blood for some time after the subsidence 

 of the acute paroxysms well-marked non-motile bodies 

 with rounded ends, in shape like a slightly curved sausage ; 

 these are the so-called " crescentic bodies " or " crescents." 

 The long diameter of the crescent is greater (|) than that 

 of a red corpuscle, the protoplasm is finely granular, and 

 contains at about the centre several well-marked pigment- 

 granules. The extremities of the crescent often appear 

 to be joined by a delicate bowed membrane (Fig. 63, / and 

 j, and Plate XXIX, b) ; this is the remains of the blood- 

 corpuscle in which the parasite has developed. 



When a " wet " specimen of malarial blood from a 

 case of pernicious or subtertian malaria is kept under 

 observation (p. 651), it not infrequently happens that 

 after a time the so-called flagellated " bodies " make their 

 appearance. These consist of a central protoplasmic mass 

 attached to which are from one to six delicate flagella 

 measuring 20-30 //, in length (Fig. 58, c). The flagella 

 are actively motile and disturb the corpuscles, but the 

 body itself does not move much. Frequently one or 

 more of the flagella break away and swim free, remaining 

 active for several hours. The flagellated bodies are never 

 seen in the freshly drawn blood, and Ross found that 

 flagellation does not occur if the finger be pricked through 

 a spot of vaseline, the blood remaining covered with the 

 film of grease. Careful observation has shown that the 

 flagellated bodies develop from " crescents " in subtertian 

 malaria, and from special rounded parasites, difficult to 



