522 



A MANUAL OF BACTERIOLOGY 



by the Italian observers, viz. the pigmented and the 

 unpigmented quotidian and the malignant tertian, but 

 this is not generally accepted) is much smaller than the 

 quartan or benign tertian, and when it reaches the stage 

 of multiplication it disappears from the peripheral blood 

 and collects in the internal organs, spleen, liver, cerebral 

 capillaries, and bone-marrow. It is actively amoeboid, 

 seems to change its position within the corpuscle, and 

 the pigment-granules are very fine in the young parasites, 



g h j 



FIG. 64. The sub-tertian parasite : a, b, c, amoebulse ; d, sporo- 

 cyte ; e, free spores ; /, g, h, female gametocyte ; j, k, I, 

 male gametocyte. (After Rees.) 



but early aggregate into large clumps. The fission forms 

 (d, e) are only met with in the internal organs. Multiple 

 infection of the corpuscles may also occur. The corpuscles 

 often suffer severely from the infection, some being shrivelled 

 and spinous, others dark in colour, " brassy " ; they may 

 also be altered or destroyed without being actually invaded 

 by the parasite. It is in this form that the crescentic 

 bodies appear (/, j). These, however, are not met with 

 at the very commencement of the attack, but appear in 

 a week or so, and may not disappear until some weeks 

 after the termination of the attack. This parasite is met 

 with in the sub-tertian, or so-called malignant, types of 

 fever, which are characterised by irregularity of the fever, 



