Proteosoma to Birds ly the Mosquito. 449 



part of the gland contained the threads. In several instances, where 

 one gland has been exposed entire, the middle lobe alone has been 

 involved ; bat in the majority all that can be stated with certainty is 

 that the cells in one portion of the gland contain threads, and that 

 those in other portions do not. 



On these points I have satisfied myself by repeated examination, 

 though the appearances are by no means difficult to make out. 



I have gone at some length into the description of this matter, as, 

 so far, we have found no satisfactory method of making permanent 

 preparations. All the preservatives at our disposal, with the exception 

 to some extent of weak formalin solution, wrinkle up the delicate cells ; 

 and I have no confidence in this agent as a means of making perma- 

 nent specimens. 



The following specific observations made by myself on mosquitoes 

 dissected by Major Ross, Dr. Bivenberg, of the American Mission, 

 who is working with Dr. Ross, and myself may be of interest : 



(a) Coccidial cysts full of apparently mature germinal threads ; no 



ruptured cysts ; no germinal threads in the body-fluids or 



salivary glands. Two observations. 

 (//) Cysts full of germinal threads ; other ruptured empty cysts ; 



germinal threads in body-fluids ; germinal threads in salivary 



glands. Over twenty observations. 



(c) Empty cysts in stomach wall ; germinal threads in body-fluids of 



thorax; germinal threads in salivary glands; no cysts still 

 containing germinal threads. Two observations. 



(d) Empty cysts only in stomach wall ; no germinal threads in body 



cavity ; no germinal threads in well exposed salivary glands. 

 One observation ; the mosquito had been infected four weeks 

 before death. 



These observations fully confirm Ross's statement in every point. 

 They indicate that the threads are formed in the coccidia ; and that 

 the germinal threads escape into the body cavity on the rupture of 

 the coccidia, to be again collected in the salivary glands. 



I should have liked to extend the series, but the continued cold 

 weather renders it improbable that I shall be able to do so before I 

 leave. 



10. The infection of birds free from Proteosoma by the bites of 

 mosquitoes. 



On December 20, the day before my arrival, twenty-two birds were 

 examined and found free from Proteosoma. On that night some of 

 these birds were used for feeding the mosquitoes which had been 

 infected on November 30 (?) and on the 24th and subsequent days ; 

 the remainder of the birds were used for feeding the mosquitoes first 

 infected on November 30 and December 10, 12, and 15. In other 



