MALARIAL PARASITOLOGY 



507 



of capsule at times. The ends stain more deeply in methylene blue than 

 the rest of the parasite, a phenomenon which is known as polar staining. 

 The pigment is quiescent in the fresh specimen. Upon prolonged 

 observation, say twenty minutes or less, according to temperature, etc., 

 these crescentic bodies are transformed into spherical bodies; the pigment 

 of certain ones of these becomes actively motile, due to internal agita- 

 tion of the chromatin fibrils, which will presently emerge as flagella. 

 Their movements are very rapid, corpuscles are knocked about, and 

 finally these flagella, which represent the male sexual element, the 

 spermatozoid, so to speak, become detached and go in search of the 

 female element. In birds one may actually observe the process of 

 conjugation in slide preparations even without the aid of a moist cham- 

 ber and heat. This transformation of crescentic bodies never occurs 

 in the human blood. It will be seen that it belongs to the sexual cycle 

 which occurs in the stomach of the mosquito. 



FIG. 153 



O 



.Estivo-autumnal type : 1 to 7, various young non-pigmented forms ; 8 to 10, larger forms from 

 peripheral blood ; 11 to 14, various ovoid bodies ; 15 to 17, crescentic bodies ; 18 to 19, crescentic 

 bodies after removal of pigment showing chromatin filaments in achromatic zone ; 20 to 21, abnor- 

 mal forms. 



Crescents do not, in my opinion, ever divide, either agamogenetically 

 or otherwise, in the blood. Forms which show a constriction are rather 

 to be referred to a twin maturation. Nor do I believe that the chro- 

 matin of microgametocytes ever divides by segmentation; it seems to 

 me that the coiled-up filaments are rapidly rearranged and then indi- 

 vidually extended as so many flagella or microgametes. 



In fatal cases the formation of crescents may not take place; tin- 

 blood infection with young parasites is then enormous, every field of 

 the microscope showing numbers of them. 



In the study of a?stivo-autumnal fever it is to be remembered that 

 crescents when found indicate that the disease is of some standing, for 

 such sexual forms (gametes) are not formed until the asexual propaga- 

 tion is waning. The recognition of these ovoidal and crescentic bodies 

 is easy. But as there are no readily discoverable pigmentecl forms in 



