100 UNIVERSITY OF WISCONSIN STUDIES 



that the predominant organism of the intestinal tract is the 

 low ratio or B. coli type. 



Figure 7 indicates that the saccharose fermenting type is 

 more common in bovine than in human feces. It is not safe, 

 however, to put too much weight on this deduction. If we 

 were to assume that the failure to ferment saccharose in- 

 dicated human origin, we would be obliged to conclude that a 

 majority of the B. coli cultures from milk came from human 

 feces. Unequal rates of multiplication by the different types 

 may completely rearrange the original relations. 



The origin of the cultures of the two groups into which non- 

 liquefying high ratio cultures have been divided is perhaps of 

 some significance. Of the 139 adonitol-)- cultures, 33 per 

 cent were from human feces, 33 per cent from water, 23 per 

 cent from milk and only 10 per cent from grains. On the 

 other hand, 74 per cent of the adonitol cultures were from 

 grains and none at all from feces. In other words, all of the 

 high ratio non-liquefying cultures from feces fermented 

 adonitol while nearly all of those from grains failed to fer- 

 ment this alcohol. If we assume that the 14 adonitol -f cultures 

 found on grains came originally from feces, AVC have a sharp 

 distinction between the fecal and non-fecal types. In water 

 and milk the fecal type predominates. It is not surprising 

 that this should be so since the greater part of the colon- 

 aerogenes cultures isolated from waters would naturally come 

 from samples more or less infected with fecal matter. It 

 may seem peculiar that so large a percentage of the fecal type 

 occurred in milk while they were very rare in bovine feces, but 

 this anomaly may perhaps be accounted for by the difference 

 in rates of growth of different types. Mr. Avers has observed 

 that while high ratio cultures will not be found in bovine 

 feces by the usual methods of plating, milk infected with 

 this material and incubated at a low temperature for twenty- 

 four hours may contain large numbers of this type. 



It will, no doubt, be suggested that the adonitol cultures 

 are merely fecal cultures Avhich have become attenuated 

 through existence under the unfavorable conditions found in 

 the soil, on the surface of grains, or in water. We have no 



