14 
Journal of Agricultural Research 
Vol. IX, No. i 
all agglutinating power for suspensions of abortion bacilli had disap¬ 
peared. 
Contrary to this, the agglutinating power of the cow’s blood serum 
remained constant for dilutions of i to 400. Not so, however, with 
the agglutinating power of material from her udder. Colostrum, as 
has been seen, agglutinated in dilutions, injected quarter, 1 to 25,600; 
other quarters 1 to 1,600. The milk as early as June 8, or 13 days 
after parturition, was positive in dilutions no higher than 1 to 200 
in the injected quarter, and 1 to 50 in the other quarters, at which 
points it remained fairly constant. 
The most interesting fact about this cow was that parturition was 
associated with retention of the afterbirth, which, on removal, was 
found to contain much abnormal material of a yellowish color, and 
this was proved to be infected with abortion bacilli. Vaginal discharge 
from the cow was also proved to be infected with abortion bacilli on 
June 1, 3, and 12, and free from infection on and after June 20. 
THE UDDER AS A POSITIVE CHANNEL OF INFECTION 
This one cow illustrates a number of abortion-disease phenomena. 
First, the introduction of abortion bacilli into the udder through the 
teat, though a method of injection was used which almost certainly 
precluded mechanical injury, positively infected it and caused the 
gradual development of agglutinating power for suspensions of abortion 
bacilli in the blood serum. In other words, the udder is a possible 
channel through which abortion bacilli may penetrate into the body. 
Second, the passage of abortion bacilli from the udder to the uterus 
is an experimentally demonstrated fact. The writers have already 
stated that, in all cases in which they found abortion bacilli in the uterus 
after seemingly normal parturitions, the cows had infected udders; 
and it is only necessary to add that, in practically half of the cows with 
infected udders that have been examined relative to this matter, the 
uterus and placenta were infected with abortion bacilli. 
It has been suggested that the abortion disease may perpetuate itself 
through abortion bacilli that enter the udder through the teat. When 
we consider how cows are milked, and how the milker goes from cow 
to cow without disinfecting his hands, and that the udders of cows are 
the commonest habitat of abortion bacilli, this mode of infection can 
not be regarded too lightly, or as an untenable supposition. That this 
is a means of perpetuation has not been proved, but it should be con¬ 
sidered as a possibility. 
In the third place, the record of cow 1154 illustrates another fact— 
namely, the high agglutinating power of colostrum from cows with 
infected udders. This phenomenon, together with the rapid decline of 
agglutinating power of material from the udder as milk takes the place 
of colostrum, has been repeatedly observed. 
