326 APPLICATION OF METHODS OF BACTERIOLOGY 



1 : 1000 sublimate solution, and finally in ammonium sul- 

 phide, and then prepare plates from scrapings from the 

 points mentioned. 



In what way do the results of these experiments differ 

 from one another? 



To what are these differences due? 



What have these experiments taught? 



In making the above experiments it must be remembered 

 that the strictest care is necessary in order to prevent the 

 access of germs from without into our media. The hand 

 upon which the experiment is being performed must be 

 held away from the body and must not touch any object 

 not concerned in the experiment. The scraping should be 

 done with the point of a knife that has been sterilized in 

 a flame and allowed to cool. The scrapings may be trans- 

 ferred directly from the knife-point to the gelatin by means 

 of a sterilized platinum wire loop. 



The brush used should be thoroughly cleansed and always 

 kept in 1 : 1000 solution of corrosive sublimate. It should 

 be washed in hot water before using. 



