XIII, B, 1 



Barber: The Transmission of Malaria 



23 



It will be noted in Table X that carrier Sin Tee was capable 

 of infecting mosquitoes even after the percentage of crescents 

 had fallen to 1.1, while carrier Plantation No. 1 apparently ran 

 out of viable gametes and failed to infect even when the per- 

 centage of crescents was as high as 7.8 and a fair number of 

 mosquitoes of susceptible species were exposed, all known to 

 have taken blood. Plantation No. 1 was probably getting more 

 quinine than Sin Tee, but as numerous experiments have shown, 

 quinine apparently has little effect on gametes further than to 

 increase the rate of their disappearance. 



Table XI includes similar data of another crescent carrier, 

 patient 537. Here only one species was exposed to the carrier, 

 A. rossi type Giles "probable" (see discussion preceding Table 

 II). In part of the cages only "blooded" females, separated 

 after one feeding, are included. Other cages were exposed twice 

 on succeeding days, and the females known to have taken blood 

 were not segregated. The number of "blooded" mosquitoes 

 surviving to be dissected appears in the last column of the table, 

 data worthy of note but of little value for comparison, since the 

 time intervening between feeding and dissection varied from 

 three to thirty days. 



Table XI. — Gamete carrier 537. All A. rossi. 



Date of feeding. 



February 26 



February 26 and 27.... 



February 27 



February 27 and 28.... 



February 28 



February 28 and 29.-. 



March 2.— - 



March 3 



March 3 and 4 



March 4 and 5 



Cres- iTimes ex 

 cents, i posed. 



I 

 I 



Per 



cent. 



29.9 



35.2 



35.2 



27.7 



27.7 



22.8 



10.8 



9.6 



5.1 



1.7 



Known to 

 have taken 



In cacre 

 after 



blood. | feeding. 



Dis- 

 sected. 



All 



76 



22 



26 

 4 

 3 

 2 



12 

 4 

 2 

 1 



13 



All 



31 





All 



20 





All 



27 

 7 



do 







Positive. 



Average 

 oocysts 

 per posi- 

 tive gut. 



-L 



Per cent. 

 18.2 

 38.5 



0.0 

 33.8 



0.0 

 50.6 

 25.0 



0.0 



100.0 



69.2 



4.8 

 31.5 



0.0 

 50.0 



0.0 

 10.0+ 



2.0 



0.0 



1.0 



3.0 



It will be noted in Table XI that carrier 537 also retained 

 viable gametes until the percentage of crescents had dropped to 

 5.1 and, at the second feeding, to 1.7. In both Table X and 

 Table XI it will be noted that there was a tendency to 

 decrease the average number of oocysts as the percentage of 

 gametes decreased, but there was no corresponding decrease 

 in the percentage of mosquitoes infected. It will be also noted 

 in both tables that the percentage of positives among mosquitoes 



