>93 
ESTIMATION OF GAMETES 
The estimation of the number of gametes ingested by the 
mosquito gives one an idea as to the grades of infection to be 
encountered in the mosquito, and this has indirectly a practical 
bearing which will be discussed later. 
Leucocyte counts taken during convalescence in malarial fever 
generally show a number not far removed from the normal. It was 
possible, then, to estimate the number of gametes by counting the 
number met with while enumerating the leucocytes during the 
differential count. Such a gamete count was made from the blood 
of every patient bitten. 
Mosquitos were weighed before biting and after biting, and the 
amount of blood ingested estimated in this way. 
Weights of Mosquitos 
Ce. albimana bred in laboratory, twenty-four hours old, mid-gut 
empty ... ... ... . 
Ce. albimana bred in laboratory, moderate blood feeding. 
Ce. albimana caught in labour-cars, some blood in mid-gut, half 
developed ova . 
Ce. albimana caught in labour-cars, much blood and early 
development of ova ... . 
Ce. albimana caught at barracks, blood in mid-gut, no development 
of ova . . 
Ce. albimana caught at barracks, blood in mid-gut, no development 
of ova . 
Weight. 
00008 
00016 
0-0019 
0-0035 
o-oo 18 
0-0021 
The average weight of mosquitos twenty-four hours old was 
0-ooo8 gramme, while the average weight of mosquitos from the same 
brood that had bitten and taken a moderate amount of blood was 
crooi6 gramme. The average weight of blood ingested being then 
1 ' 08 gramme, approximately o-ool gramme. Assuming the specific 
gravity of blood in malarial fever with slight anaemia to be 1 050, then 
105 : 100 : : 00008 : 0000761 = the volume of 0-0008 gramme of 
blood. Now if there were 22 gametes per 100 leucocytes, as in 
Experiment 38, and 6,500 leucocytes per mm. 3 as they were, 
by actual count, there would be 22x65x0-761 = 1088 gametes 
ingested. If, under the most favourable circumstances, there are 
equal number of male and female gametes, there should have een 
about 1,632 zygotes in this mosquito’s mid-gut after three ee ings, 
