236 INTESTINAL BACTERIA 
tinal flora. Much work has been done by various investigators from 
which facts have been well established with regard to changes induced 
in the intestines by variations in the diet. The changes in the flora 
resulting from various diets have been measured in terms of certain 
large groups and rarely in terms of any one or few organisms. These 
groups which have thus been used may be enumerated as follows: 
I. Putrefactive Group 
Bacillus colon, B. Welchir 
II. Aciduric Group 
B. bulgaricus, B. acidophilus, B. bifidus 
III. Amylolytic Group 
Glycobacter amylolyticus 
Herter and Kendall (1908), working with monkeys, studied the effect 
on the intestinal flora of sudden changes in the diet. After the flora 
from a distinctly protein diet had been established the diet was changed 
to a milk and sugar diet. From this change they were able to detect 
a change in the intestinal flora and mental condition of the animal. 
Also in the urine, putrefactive products were quite evident. In the 
intestines the acidolphile group of organisms was changed to a proteo- 
lytic group. This was one of the first papers from which definite con- 
clusions could be drawn. The authors suggest that in a disease where 
either the acidophile or putrefactive group tends to become established, 
a rapid alteration in the diet would tend to prevent either group of 
bacteria from becoming established. The same conclusions were reached 
by Herter (1910) in a later paper. 
Blatherwick and Hawk (1914) have studied the effect of fasting and 
of low- and high-protein intake on the bacteria in the intestines. The 
concentration of bacteria was measured by determining the amount of 
bacterial nitrogen in the feces according to the method mentioned else- 
where in this chapter and the output of urinary indican. They found 
that there was no relation between the output of bacteria in the feces 
and amount of indican in the urine. By means of a seven-day fast 
(Blatherwick and Hawk, 1914), the bacterial nitrogen excreted by a 
76 kg. man was reduced from 1.571 gms. to 0.101: gm. The actual 
weight of excreted bacterial substance was reduced from 14.336 to 0.920 
gm. per day. The output of bacterial nitrogen and bacterial sub- 
stance was about the same during a fast and on a low proten intake. 
Assumption of a high protein diet caused an increase in the above figures. 
