228 



LATENCY OF AFRICAN COAST FEVER. 



development by sporogony continues through the nymphge within 

 which the sporozoites are formed, and terminates the sporogony 

 stage. 



In March, April, May, June and July the sporozoites are 

 transmitted by the nymphse to their bovine hosts. Prolific pro- 

 duction of the parvge then takes place, owing to the reinforce- 

 ment which they have received during the sexual cycle ; the 

 red blood cells are intensely infested, and the microscopical ex- 

 amination of the blood no longer fails to yield positive evidence 

 of their presence. We have now the schizogonal stage — if I am 

 right in my conclusions; this is continued endo-corpuscularly. 



NUMBER OP OUTBFEAI^S OF APPilCAU COAST rSV^. AGGREGATED INTO MONTHS. 



Period 

 < 



of sporogony 



Period 



of 



sporogony 

 > 



Tropozoites, schizonts, and merozoites are successively formed. 

 As the year advances — that is, about August or thereafter — the 

 tropozoites or schizonts gradually form themselves into Koch's 

 bodies for the purpose of passing a quiescent period, and remain 

 resistant to external influences up to the end of November ; in 

 December they again become active, or rather, the sexual func- 

 tions are completed, and separation from the tissues begins 

 anew. Therein is at least an explanation of the irregular re- 

 sults noticeable in many of the temperature camps. 



The continuance of coast fever after herds have been freed 

 of their infected units and febrile cases, and been subjected to 



