The Disinfectant Action of Glyceral. 91 



antiseptic properties." F. R. Blaxall reported a similar study in 

 1902-3, his work including only one concentration of glycerol, 

 50 per cent. More recently G. Mathers and G. H. Weaver have 

 noted the remarkable viability (14 to 30 days) of various micro- 

 cocci and streptococci in 50 per cent, glycerol suspension, and the 

 persistence of the organisms for 90 days on blood agar lightly 

 covered with 50 per cent, glycerol. 



Our own work was undertaken in connection with the study 

 of the specific effects of salt solutions upon the permeability of 

 bacterial cells, and in connection with this investigation the 

 effect of glycerol in concentrations varying from 9.2 per cent, to 

 100 per cent, has been determined, Bacillus coli being the test 

 organism. 



The glycerol used was an analyzed commercial preparation 

 (Merck) with maximum limits of foreign substances .1814 per 

 cent. The analysis showed absence of carbonizable matters, 

 and heavy metals. Pure, ammonia free water was used in making 

 solutions, and for the controls. 



Glycerol solutions of varying concentrations (9.2, 27.6, 46.0, 

 64.4, 82.8, 100 per cent.) were made up in 50 and 100 c.c. portions. 

 Young cultures of B. coli (16-20 hours) were washed from agar 

 slants with 2-3 c.c. of the test solution. One c.c. of this suspen- 

 sion was added to the bottles of the solution, and after dilution, 



Viability of Colon Bacilli in Glycerol Solutions of Varying 

 Concentration. 



Concentration of Glycerol. 



O 



9.2 per cent 

 27.6 per cent 

 46.0 per cent 

 64.4 per cent 

 82.8 per cent 

 100.0 per cent 



Percentage of Number Originally Present Found After 



2-3 Hours. 



99 

 82 

 117 

 87 

 75 

 S3 



4-5 Hours. 



108 

 118 



77 

 41 

 38 

 4 



5-7 Hours. 



114 



55 

 18 

 IS 



8-9 Hours. 



SO 

 10 



6 



•35 



18-24 Hours. 



146 

 185 

 52 

 17 

 S 

 4 



.005 



agar plates were made. The solutions were incubated at 37 0 , 

 one c.c. portions being removed at definite time intervals and 

 plated after dilution. The test solutions up to 64.4 per cent, 

 were shaken carefully by hand before removing the portion to be 



