MYZOMYIA ROSSII AS A MALARIA CARRIER. 



281 



No. 



Date of feeding on 

 patient's blood. 





1 Patient 

 took 1.5 p rfi 



fc° f elapse 



h dro ter sl,ckin S 



Iper day— 



Days. 



November^ ! 9 



November 5 I 11 



(November 6 12 



[November 9 15 



November 7 13 



(November? 13 



(November 10 [ 16 



Novembers 14 



November 13 | in 



do 19 



do 19 



do 19 



Days, krs 

 5 



Percent- 

 age of 



NaCl in 



water 



from 



which 



mosquito 



was ob- 

 tained. 



Result of the experiments. 



4 









1.3 



s 



: 



} 



1.3 













0. 65 



8 









0.6 



5 









0.6 



11 









0-.6 



5 









0.6 



5 









(") 



9 









( b ) 



9 









( b ) 



Ookinetes; stained with Giemsa. 



Numerous young oocysts on stomach 

 prep, in glycerine. 



Many well-developed oocysts and some 

 almost ripe; preparation stained 

 with alumcarmine inclosed in Cana- 

 da balsam. 



One oocyst in stomach wall; prepara- 

 tion lost in further treatment. 



■One doubtful oocyst in stomach wall. 



No infection. 

 Do. 

 Do. 

 Do. 

 Do. 



a Unknown. 



b Fresh, probably rain water. 



Only a small number of mosquitoes were, examined. Many larvse 

 did not develop, while the females which hatched were with difficulty 

 kept alive for any length of time, and not a single one until the stage 

 was reached in which sporozoites appear in the salivary gland. It is 

 also true that some specimens were used for determining the species. 

 A small number of the females could not be induced to suck the blood, 

 and many of the specimens that did so died every day, so that very 

 little resulted from our plan to examine different specimens at regular 

 intervals in order to observe the whole course of development. It is 

 extremely difficult to isolate the stomach even, within a few hours after 

 death. As I feared that the mosquitoes would not remain alive until 

 the day fixed for their examination, the few remaining specimens were 

 dissected in advance of that time. All this is to be regretted; for, 

 whereas certainty might have been obtained, as.it is, the results allow 

 only of conjecture as to what effect the percentage of salt in the breeding 

 places has upon the liability to malarial infection of the mosquitoes. It 

 is true that the two mosquitoes taken from water containing 1.3 per 

 cent sodium chloride were found to be strongly infected. In a few 

 specimens taken from water with 0.6 per cent sodium chloride, the 

 infection was either mild, dubious, or entirely absent, while not a single 

 one of those obtained from fresh water proved to be infected. However, 

 as it happened, those from water containing 0.6 per cent sodium 



