86 THE UNR^RSITY SCIENCE BULLETIN. 



It is quite evident that human blood gave the most positive 

 results. 



I decided, as mentioned above, to use pigmentation as the 

 primary method of division and blood agar plates secondarily, 

 subdividing each of these into hemolytic and nonhemolytic 

 staphylococci, and the fermentation reactions as described in 

 table II were made use of for further subdivision. The results 

 of this are summarized in table IV. 



It will be observed that the white staphylococci were evenly 

 divided between hemolytic and nonhemolytic strains, 16 

 strains were hemolytic and 14 strains were nonhemolytic. 

 This condition shows a gradual change as you go through the 

 yellow and orange staphylococci. For example, out of 13 

 yellow staphylococci, one was lost before hemolytic properties 

 were determined and of the remaining 12, 9 were hemolytic 

 and 3 were nonhemolytic. Among the orange staphylococci, 

 26 strains were hemolytic and 3 nonhemolytic. Of these 26 

 hemolytic orange staphylococci, 19 were from the animal 

 body as compared with one among the three of the nonhemo- 

 lyzers. Of the 19 from the animal body, 16 were positive in 

 all sugars. Among the yellow, only one was from the animal 

 body and that one was nonhemolytic and fermented dextrose 

 but not lactose or mannite. Among the white hemolytic staph- 

 ylococci, 7 were from the animal body and of these 7, 6 fer- 

 mented all sugars. Among the 14 nonhemolyzers, 2 were from 

 the animal body. This suggests that in general staphylococci 

 associated with the animal body seem to be hemolyzers. The 

 history of organisms obtained from the air and various foods 

 is not known further than the source mentioned. 



As the fourth phase of this problem, we have attempted to 

 study a possible classification of staphylococci, making use of 

 pigment as a primary division and next the ability of the 

 staphylococci to produce proteolysis or conversely failure to 

 produce proteolysis. This is followed by making use of car- 

 bohydrates as in previous tables. It will be observed that the 

 only difference between this and the third phase is that pro- 

 teolysis is substituted for hemolysis. 



Very little work has been published showing the use of milk 

 agar plates in the attempt to classify any kinds of bacteria 

 at all. As a preliminary it was found necessary to determine 

 the optimum reaction of media for proteolysis. Accordingly, 

 studies were made on milk plates +2, +1, 1, and — 1 to 

 phenolphthalein. The results are summarized in table V. 



