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- 
liquetying 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 + cultures 
found on grains came originally from feces, we have a sharp 
distinction between the fecal and non-fecal types. In water 
and milk the fecal tvpe 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. Ayers has observed 
that while high ratio cultures will not be found in bovine 
feces by the usual methods of plating, milk infeeted with 
this material and incubated at a low temperature for twenty- 
four hours may contain laree numbers of this type. 
It will, no doubt, be suggested that the adonitol— eultures 
are merely feeal cultures which have become attenuated 
through existence under the unfavorable conditions found in 
the soil, on the surface of grains, or in water. We have no 
