13 
sively that the bacteriological flora of feces is subject to fre- 
quent changes at different times of the year. We now proceed 
to a study of the actual bacilli isolated. Table No. II (c) 
gives the result in percentages. 
It will be seen that Table II (c) goes into much greater 
detail, and gives the percentage prevalence of separate organ- 
isms in the various series. A large number of very inter- 
esting points are demonstrated by this table. The most 
striking feature is the continual and steady presence of the 
Grunthal group, the coscoroba group, and, to a less extent, 
the coli group. Wide variations in percentage occur, however, 
and even entire absence of these bacilli is recorded in some 
series, but these organisms undoubtedly form the bulk of 
those present in dejecta of man and cattle. The main interest 
of this study, however, lies in the presence or absence of the 
rarer bacilli ; in this connection much has yet to be discovered. 
Great variations, both in number and kind, occur in the 
flora of feeces at different times of the year. Compare, for 
instance, the results of series Nos. r and g taken in July 1908 
and March 1909; note the very rich mixture in the human 
feces in No. r and the few varieties in No. 7. Observe the 
relative number of coli communis in the two series ; also the 
number of cloace, and the number of coscoroba. The changes 
noticed to some extent apply to both human feces and cow- 
dung. Both human feces and cowdung show a considerable 
falling-off in coli communis and in cloace ; on the other hand, 
both show a very great increase in such organisms as cosco- 
roba. Another most striking example of the rapid change 
of the flora of the intestine of man and animal is to be found 
in series No. 3. This change is not so much in quantity as 
in quality. 
We wish to lay stress on the fact that experience has 
shown that there are ‘‘ epidemics ’’ of certain organisms in 
the feces both of man and animals. For instance, in the 
dry weather of 1908 in Madras bacillus cloacee were extremely 
common, especially in the dejecta of cattle. Later on, in 
December of the same year coscoroba became extraordin- 
arily prevalent. Quite recently, in the monsoon of rgII, coli 
communis predominated in human feces to a very great 
