1062 



PATHOGENIC PROTOZOA 



Fertilization inside the cyst has not been demonstrated, nor has 

 any other sexual process or conjugation been shown to occur. 



In size the cysts from different patients vary considerably, so 

 much so that well recognized races or pure lines occur : Dobell and 

 Jepps (1918) describe five such races, the cysts of which have 

 average diameters of 6.6 microns, 8.3 microns, 11.6 microns, 13.3 

 microns and 15.0 microns. 



The Dysentery Carrier. Both convalescent and healthy contact 



FIG. 126. ENTAMCEBA COLI. 



Typical nucleus. (Army Med. School Collection, 

 Washington, D. C.) 



carriers are known, and recent experiments have shown that they 

 are not infrequent, even in the absence of cases of chemical dysen- 

 tery. To explain the carrier state, it is of course necessary to 

 predicate some insignificant and silent lesions in the colon of the 

 apparently healthy man. There the first part of the life history 

 is lived through and the parasites which come to lie in the lumen 

 of the intestine encysts and are found in the feces. 



The treatment of amoebic dysentery, to be effective, must be radical 

 and persistent, and may be compared to the treatment of malaria 

 with quinine. For many years the English in India, with a few 



