1350 Wisconsin Academy of Sciences , Arts , and Letters. 
method. In milks pasteurized in the bottle, A 3 and A 4 , all the 
plates made remained sterile, which was in correspondence with 
the fermentation-tube tests. 
It seems that there is quite a close resemblance between the re¬ 
sults obtained in test for B. coli by the Endo plate method, and 
the lactose petoone bile. Ayres and Johnson^ find that there 
are anaerobic bacteria in milk, which resists pasteurization that 
give gas in the bile fermentation tests which might be confused 
with B. coli, and suggest that where B. coli tests are used to con¬ 
trol pasteurization that complete cultural determinations be 
made of suspected colon forms. 
The simultaneous use of lactose bile and Endo’s medium would 
be strong evidence of B. coli in case a positive result was ob¬ 
tained in each, and would enable one to arrive at a definite 
opinion considerably sooner than would be possible if it were 
necessary to test out all gas formers found in lactose bile. The 
particular difficulties come in the use of this medium due to 
the troublesomeness of its preparation, and difficulty of using 
relatively large amounts of milk (1 c. c.). 
4. Bact. Welchii. Savagef has suggested that Bact. Welchii 
( B . enieritidis sporogenes ) is of importance in that it is a valu¬ 
able means of measuring the manurial pollution of milk, since 
the spores of this organism are prevalent in manure and in dust, 
while they are absent from milk collected under conditions of 
great cleanliness. Accepting this as a statement of fact, it 
seemed that this organism might be a measure not only of the 
cleanliness of raw milks, but it may also be used in the case of 
pasteurized milks to indicate the original character of the milk 
before being heated. In other words, it seemed as if we might 
have in this organism a means of judging the original character 
of the raw milk by examining the pasteurized milk. Savage! has 
also suggested a quantitative method of estimation. A modifi¬ 
cation of Savage’s outfit has been described above (see p. 1320), 
and was used throughout this investigation. 
The method used of recording results is that suggested by 
Savage, and is as follows: Twenty c. c. of the milk, having been 
* Ayers and Johnson: A Study of the Bacteria Which Survive Pas¬ 
teurization”. Gov’t. Printing Office, Wash., 1913, p. 60. 
f Savage: Milk and the Public Health. The Macmillan Co., 1912. 
t Ibid., p. 189. 
