STERILISATION 101 



These figures cannot be taken as absolute. The resistance capacity 

 of bacteria is very variable. A species under some conditions may 

 be three or four times more resistant than it is under other conditions. 

 The same naturally applies to a collection of species, such as Miquel 

 worked with. We must therefore allow for this and, for instance, 

 interpret 1 : 4 as ranging between 1 : 6 and 1 : 2. The table, however, 

 is valuable as indicating the average antiseptic value of various 

 substances. 



Finally, mention must be made of some of the interesting and 

 homely substances which enter into the common round of daily life. 



Alcoliol. The germicidal value of alcohol has been greatly over- 

 rated. Thus Sternberg finds that even a 95 per cent, solution acting 

 for 48 hours failed to kill bacterial spores. Absolute alcohol had 

 absolutely no effect on anthrax spores, even when the latter had 

 been immersed for 110 days. In the proportion of five parts of 

 absolute alcohol to one part of tuberculous sputum, the latter was 

 rendered innocuous only after 24 hours. 



Camphor. This substance also has very little germicidal value 

 as shown by the fact that such delicate organisms as typhoid bacillus 

 and cholera spirillum were destroyed only after 8-10 days' exposure 

 to the action of essence of camphor. The same remark applies to 

 oil of camphor and tincture of camphor. 



Coffee Infusion is an undoubted germicidal agent as evidenced 

 by the following results : 



1. A three per cent, solution restrained the growth of typhoid 



bacillus, and a five per cent, solution killed it after two 

 days. 



2. Cholera failed to grow in a one per cent, solution. 



3. Proteus vulgaris (a common sewage organism) failed to grow 



in a nutrient solution containing 2'5 per cent, of coffee 

 infusion, and was killed outright after two days, when the 

 nutrient solution contained ten per cent, of this infusion. 

 These results are interesting and gratifying in view of the popularity 

 of this palatable beverage. 



Oil of Lavender, Eucalyptus, Rosemary, Cloves. These four sub- 

 stances are stated to be the best antiseptics among the essential 

 oils. 



Glycerine is not a good antiseptic, and in fact in small quantities 

 it favours the growth of the bacillus of consumption. In the pro- 

 portion of about 25 per cent, it hinders, but does not stop putrefactive 

 decomposition. 



