Abstract
Glycerol was employed as a preliminary to the study of an agent capable of destroying the infective but not the immunizing property of the virus of experimental typhus fever in the guinea pig.
Fragments of brain removed from typhus-infected guinea pigs on the second day of the fever were immersed in 1, 5, 10, 25 and 50 per cent sterile glycerol, and placed at a temperature of about 6° C. After a period varying from 7 to 22 days in the case of the lower dilutions, and from 7 to 58 days in the case of the 50 per cent dilution, approximately 2,000 minimal infecting doses of the virus contained in the washed glycerolated brain tissue were injected intraperitoneally into normal guinea pigs. The results in all cases showed that the brain was deprived not only of its infective but also of its immunizing action.
The etiological significance in typhus fever, lately ascribed to Bacillus proteus X19 by several investigators, suggested a test of the influence of glycerol on this micro-organism. Accordingly, 24 hour agar slant cultures of Bacillus proteus X2 and X19 were washed off with the same dilutions of glycerol as had been used in the case of the typhus virus, and the glycerolated cultures were kept in the ice-box. At weekly intervals sub-plants were made on agar plates of 0.2 cc. of the glycerol suspensions. After 31/2 months an infinite number of colonies was noted in the case of both strains, and in all dilutions, except that of 50 per cent, from which no growth could be obtained after one month.
The resistance of the bacilli contained in the brain was tested by injecting cultures of X, and XI, strains intraperitoneally into normal guinea pigs.
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