MODIFICATION OF BIRD MALARIA INFECTIONS 407 



about 0.05 of a cubic centimeter of a normal saline dilution of 

 infected blood being made in the peritoneal cavity. The blood was 

 obtained from a vein on the inside of the leg. An effort was made 

 to eliminate environmental and other conditions which might 

 aft'ect the normal course of infection. Riddle and Honeywell 

 (1923) found that blood sugar in pigeons changes with exposure, 

 sex, ovulation, etc., and Boyd (1925) suggested that excessive 

 bleeding might account, in part, for the variations in the normal 

 course of infections observed by other workers. The work re- 

 ported here seems to confirm this suggestion. Birds bled for 

 quantitative work very frequently show heavy infections. 



It seemed that the simplest way to increase the sugar content 

 of the blood is to feed birds a solution of glucose. Ten grams of 

 glucose were dissolved in ten cubic centimeters of water, and 

 the birds fed four times a day at 3 :oo, 5 :oo, 7 :oo and 9 :oo p.m. 

 This covers most of the period of merozoite formation when the 

 parasites might be expected to be most easily affected by a change 

 in the culture medium (the blood). It was found that changing 

 the sugar content of the blood at any time except during the 

 time of merozoite formation had little, if any, eft'ect on the course 

 of bird malaria. The birds seemed to thrive on it. A dose of 

 one-tenth of one cubic centimeter was administered on the first 

 day of the feeding of glucose at each of the four hours mentioned, 

 then increased from 0.5 to i cubic centimeter at each feeding 

 as the birds grew fond of it. They would take it even when sick. 



The method used to decrease the sugar content of the blood 

 was to inject insulin intraperitoneally. It was found that the 

 maximum dose for most birds was two units. In several cases 

 where three units were administered, one dose at eleven o'clock, 

 one at three, and one at six, the birds were unable to stand. 

 Prompt recovery in a few minutes followed the feeding of dex- 

 trose. Quantitative work has shown that birds vary a great deal 

 with respect to normal blood sugar. It is to be expected, then, 

 that the insulin should be more effective in some cases than 

 in others. 



Siiggcsted problems. Quantitative work is necessary to show 

 the relation of the blood sugar to the normal course of malaria, 

 relapses, etc. Aluch work along this line has been done with 

 canary blood, but, owing to the very small amounts of blood 

 obtainable from the birds, it would seem that this work must be 



