284 ORIENTAL PLAGUE chap. 



number of tests which I have made in this direction, marked differ- 

 ences exist in the action of a certain disinfectant, with which I have 

 been well acquainted for some years, to wit, izal, as applied to 

 microbes, such as Staphylococcus aureus, B. coli, B. typhosus, in different 

 surroundings ; in one case the microbes were taken from artificial 

 cultures, and in the other were in their natural habitat. The izal 

 used was the fluid sold as ordinary izal in the ordinary pharmacy. 



Method 



1. In the case of pus of acute abscess, the pus and blood, 

 immediately after collecting them from the abscess in sterile test 

 tube, were diluted with sterile distilled water, 1 part of pus being 

 added to 49 parts of water. From this dilution a control culture 

 was made on agar, one platinum loopful of the mixture for one agar 

 surface culture. The result of this control culture indicated the 

 amount of staphylococcus present, and allowed the number of 

 colonies in the control tube to be compared with those that appeared 

 in the culture tubes after medication. To the above dilution of the 

 pus was added a definite amount of izal direct as sold, and then 

 well shaken up. The proportion of izal to the volume of diluted 

 pus represented the strength of izal actually used in the experiment. 



2. In the case of urine a definite amount of izal was added, well 

 shaken j then, after being kept for the required time, the necessary 

 cultures were made on agar and in broth. 



3. In the case of the typhoid stool only typical fluid (pea-soup) 

 stools were used j of these a definite quantity was added to a 

 definite quantity of sterile water. This was well shaken up ; to it 

 was added a definite amount of izal as in the other cases. 



Also in the last two instances control cultures on agar with one 

 platinum loop were made from the diluted materials previous to the 

 addition of the izal, so as to be able to compare the actual number 

 of microbes of the coli-typhoid type before and after exposure to the 

 disinfectant. 



After the addition of izal, cultures were made at the desired 

 periods from the medicated fluids on agar surface and in broth, each 

 culture tube receiving three platinum loops of the medicated 

 material; these tubes were then incubated at 37° C. Inspection 

 and notification were made after the tubes had been incubated for 

 three or four days, for by this time all growth, if any, had become 

 complete. 



