288 



ORIENTAL PLAGUE 



CHAP 



Table II 



From this it follows that for Staphylococcus aureus of culture 

 izal 1 in 600 is a complete disinfectant in 5 minutes. This result 

 is in so far interesting as it shows that Staphylococcus aureus of 

 culture is disinfected quicker and with greater dilutions of izal than 

 when it is acted upon in its natural habitat, that is pus. It will 

 be remembered that for pus izal 1 in 400, 15 minutes' exposure, 

 was the limit for completely disinfecting Staphylococcus aureus, 

 whereas for disinfection of this microbe in watery emulsion 1 in 600 

 izal for 5 minutes' exposure was sufficient. 



This result emphasises the importance of testing the disinfecting 

 power of any given substance on the pus microbes while in their 

 natural media, for only thus is an absolute index for practical 

 guidance acquired. 



Second Series. — Typhoid Stools. 



Experiment 5. — Typical (pea-soup) typhoid stool (1) of a case of 

 typhoid fever, 22nd day of illness. 



This stool was tested in high dilutions by means of Drigalski 

 Conradi plates, and was found to contain about 14 millions of 

 B. coli, about the same number or a little more of streptococci, and 

 3 millions of the B. typhosus per 1 ccm. of original stool. 



The disinfection experiment was made in the following manner: — 



1 ccm. of the stool was added to 49 ccm. of sterile distilled 

 water (1 in 50) ; this was well shaken up till a fair and uniform 

 emulsion was obtained. Control agar culture with 1 loop showed 

 innumerable colonies of above microbes. To it was then added 

 0*1 ccm. of the izal and well shaken up; this made, then, a 

 dilution of 1 izal in 500. 



Cultures were made after 15 minutes', after 30 minutes', and 



