168 
ferences in technic. Some observers have found that when a number 
of animals are inoculated with the same samples of milk only one, 
perhaps, will develop tuberculosis. Some centrifugalized the milk 
and gave sediment alone, while others gave sediment and cream. 
I will not enter into the question whether the tubercle bacilli found 
in milk are virulent for man, but give my results solely as to whether 
the market milk of the city of Washington contains tubercle bacilli 
virulent for guinea pigs. For myself I object most strenuously to 
using milk containing tubercle bacilli virulent for laboratory ani- 
mals and prefer to leave the question as to their pathogenicity for 
man to be discussed by others. 
Before presenting the results obtained by me with the market milk 
of the city of Washington it will be interesting to refer briefly to 
results obtained elsewhere by others. 
REVIEW OF LITERATURE. 
Bang, B. Deut. Zeit. f. Thiermed. XI, 1884, p. 45. 
Injected apparently normal milk from the sound quarter of an 
udder another part of which was diseased, into the belly wall of two 
rabbits, which developed inoculation tuberculosis and died after 2^ 
and 3J months, respectively. This was repeated later with two more 
specimens of milk, with the same result. He also demonstrated that 
the milk of tuberculous cows without demonstrable udder lesions, 
could contain tubercle bacilli. 
Stein, G. Experimentelle Beitrage zur Infektion der Milch perlsuchtiger Kuhe. 
Inaug. Dissert., Berlin, 1S84. 
Intraperitoneal inoculation of guinea pigs with raw milk of tuber- 
culous cows. Ten negative and four positive results. In two of the 
latter tubercle bacilli were demonstrated, and two negative. Some 
of the cows had tuberculosis of the udder. 
Hirschberger, K. Experimentelle Beitrage zur Infectiositat der Milch tubercn- 
loser Kiihe. Deut. Arch. f. klin. Med., XLIV, 1889, p. 400. 
Twenty specimens of milk from tuberculous cows injected into the 
peritoneum of guinea pigs. Xone of the animals inoculated died of 
septic peritonitis. Eleven of the specimens proved to contain tubercle 
bacilli. (Other acid-fast organisms, of course, were not differen- 
tiated.) By microscopic examination only one of the specimens of 
milk was shown to contain tubercle bacilli. Tubercle bacilli oc- 
curred not only in milk from tuberculous udders, but also where 
the udders were sound, and where the cow was but slightly affected 
with tuberculosis. 
Gebhardt, F. Experimentelle Untersuchungen ueber den Einfluss der* Verdun 
nung auf die Wirksamkeit des tuberkulosen Giftes. Virch. Arch., CIX, 
1890, p. 127. 
