84 
TYPHOID FE^H:R IX DISTRICT OF COLUMBIA. 
Savage “ (1906) as the result of his investigations lound that milk 
from individual cows yielded B. coli in 17.5 per cent of the samples. 
In 11 mixed milks collected fresh at the farm and examined witliin 
three hours B. coli was present in 36 per cent, and in 16 shop samples 
and mixed milk samples, not examined at once, they were present in 
94 per cent of the samples. 
Heinemann^ (1905) considers that the lactic ferments are of intes- 
tinal origin and are present in milk o\ving to contamination with 
feces. 
MacConkey further savs that with ordinarv care and cleanliness it 
is possible to obtain milk which, when freslily draAvn, contains less 
than 1,500 organisms per cubic centimeter. 
Freslily dravm milk should not contain gas-forming organisms in 
at least 50 cc. 
Gas-forming organisms are present in milk ovdng to contammation 
with fecal matter. Of these organisms the B. oxytocus pcrniciosus, 
B. neapolitanus, and the B. coli communis occur in greatest number 
in fresh milk, while the B. cloacae and B. lactis aerogenes appear at a 
later stage. 
Out of 107 nonchromogenic lactose fermenters isolated from milk 
only one bacillus gave the reactions of the B. acidi lactici (Htippe), 
while the B. GrilntJial, B. pneumoniae (Friedlander), and the B. cos- 
coroha have not been met with once. 
It seems, then, to be the general opinion that gas-forming bacteria are 
not normally present in mhk, but that they gain access to it because 
of want of care and cleanliness during the milking and in connection 
o o 
with the various vessels in which the milk is stored. Tliis opinion is 
quite borne out by the results of the experiments detailed in this 
paper. 
Berge}^^^ (1904) collected samples of milk drawn m sterile tubes 
directlv from the udder of individual cows and showed that about 
one-third were free from bacteria, while only about 10 per cent of 
the samples contained large numbers — over 5,000 per cubic centi- 
meter. The prevailing bacteria were pyogenic organisms, and when 
in large numbers were usually associated with inflammatory reactions 
in the udder. The organisms of putrefaction and the lactic acid 
bacteria gain access to the milk after it leaves the udder. 
Bergey^ (1904) also found the species of bacteria which appeared 
to be present m freslily -drawn milk, such as staphylococci, strepto- 
o Savage, W. G., Jomn. hyg., vol. 6, p. 123. 
& Heinemann. Ref. -Bull, de I’Inst. Pasteur, vol. 4, p. 246. 
c Bergey, D. H.: The cellular and bacterial content of cow’s milk at different peri- 
ods of lactation. Rpr. Univ. Pa. med. bull., July- Aug., 1904. 
Bergey, D. H.: Sanitaiy supervision of the collection and marketing of milk. 
Ibid. 
