GRANULAR VENEREAL DISEASE AND ABORTION IN CATTLE. 27 
abortion. A cow will be served by the bull and fail to come in heat 
for two to five periods, convincing the owner that she is pregnant, 
when unexpectedly she again shows estrum. While such phenomena 
may depend upon a variety of causes, abortion unquestionably 
accounts for many of these cases. Occasionally the breeder chances 
upon the freshly expelled embryo, which may be only 3 to 4 inches 
long. Since these embryos come away inclosed within the fetal 
membranes, leaving no afterbirths, the discovery of the abortion is 
a remote possibility. 
In rare cases the fetus dies from the infection of contagious abor- 
tion but is not expelled, and the cow or heifer appears sterile. Two 
things may occur: The fetus may undergo maceration, the tissues 
break down, some pus escape from the uterus, but largely remain in 
the organ as pyometra. In other cases the fetus does not break 
down, but desiccates to form an inert foreign body known as a 
mummy (lithopsedion). 
When pregnancy nears its close abortion again may escape un- 
noticed. A fetus may be expelled alive at the eighth month, or even 
earlier, because of the presence of the infection of contagious abortion 
in the uterus, and is commonly designated premature birth, though 
in fact its early expulsion is due to precisely the same cause as that 
which causes other fetuses to be expelled dead. Or, the infection 
being present, the fetus may live and develop up to the normal date 
for parturition, die immediately preceding labor, and be expelled 
fully developed, fresh, but dead, and it is classed as a stillbirth, 
though just as evidently an abortion as is the five months' fetus, 
killed by the same infection. Abortion statistics in any herd can 
accordingly be merely approximate. 
ABORTION DATA IN HERD A. 
As a basis upon which to build an outline of the behavior of abor- 
tion in a herd, we submit statistics from herd A in Table 4 below. 
This herd at first consisted largely of grades, but was later changed 
into a pedigreed herd. The period covered is 22 years, which serves 
to afford a fair opportunity for arriving at the average rate of abortion. 
An average annual rate of 12 per cent of abortions is shown. The 
vacillations from year to year are exhibited in the diagram, figure 1, 
and the prevalence of abortion according to age in another diagram, 
figure 2. During the earlier part of the time covered the herd con- 
sisted largely of adult cows, which were bought when mature, milked 
for a time, and sold. Later it has been the policy to grow all heifer 
calves and breed them. Thus there has been latterly a compara- 
tively large number of heifers in first or second pregnancy. 
