﻿426 



The Philippine Journal of Science 



1914 



cytes were made in thick blood smears, from 1,500 to 3,000 

 leucocytes being counted. In every case the gamete count is 

 expressed in percentage of the leucocytes in the blood, and the 

 counts were made from blood preparations made at the time 

 the mosquitoes were fed on the patient. 



The counts range from 0.6 to 87.0 per hundred leucocytes. 

 This would equal approximately from 42 to 6,090 gametes to 

 1 cubic millimeter of blood, basing the estimate on an average 

 of 7,000 leucocytes per cubic millimeter of blood. In all cases 

 this would be well within the limits of infectiousness for the 

 mosquitoes as estimated by Darling (1910). In three experi- 

 ments (50, 51, and 53), owing to the fact that the mosquitoes 

 were fed on the patient at the same time that the blood speci- 

 mens were taken and before the gamete counts were made, it 

 was found that the gametes had disappeared from the blood. 

 However, in two of these experiments the mosquitoes had pre- 

 viously been fed on the same patient when his blood contained 

 gametes. 



The gametes being the only stage of the malarial parasite 

 capable of infecting the mosquitoes, it would be supposed that the 

 percentage of infections, or at least the intensity of the infec- 

 tions, would vary Avith the number of gametes in the infected 

 blood on which the mosquitoes fed. In Table VII are given 

 the percentage of infections and the average number of oocysts 

 to an infected mosquito, classified according to the gamete count 

 of the patient on which the mosquitoes fed. In this table are 

 included all of the mosquitoes dissected. 



Table VII. — Relation between the number of gametes in the blood and the 

 percentage and intensity of infection of the mosquitoes. 



Gametes in the malarial blood. 



0-6 per cent -. 

 6-10 per cent .. 

 10-15 per cent . 

 15-20 per cent . 

 20-25 per cent . 

 25-30 per cent . 

 30-35 per cent 

 75-80 per cent . 

 80-90 per cent . 

 No record 



Mosqui- 

 toes dis- 

 sected. 



566 



364 



106 



5 



27 



23 



32 



22 



22 



135 



Mosqui- 

 toes in- 

 fected. 



86 



45 



12 



5 



18 



10 



6 



9 



1 



5 



Total 

 oocysts in 

 mid-grut of 

 infected 

 mosqui- 

 toes. 



494 

 329 



39 

 185 

 622 

 200 

 153 

 196 

 4 



11 



Infected 

 mosqui- 

 toes. 



Per cent. 



15.5 



12.3 



11.4 



100.0 



66.6 



43.4 



18.7 



40.9 



4.5 



3.7 



Average 

 oocysts to 

 an infected 



mosqui- 

 to." 



5.7 



7.3 



3.2 



37.0 



35.1 



20.0 



25.5 



21.7 



4.0 



2.2 



• In the first and third numbers in this column, in 4 and 6 of the mosquitoes, respectively, 

 the salivary glands only were infected at the time of dissection. Each of these was recorded 

 as having 1 oocyst in the mid-gut, but it may have had more. 



