GRANULAR VENEREAL DISEASE AND ABORTION IN CATTLE. 25 



ledons of the uterus undergo corresponding development. The 

 intimacy of contact between the chorionic and uterine placentae grow 

 apace throughout the duration of pregnancy. Upon this fact is 

 based the common observation that when abortion occurs before the 

 fetus has reached or materially exceeded 12 inches in length it is 

 ordinarily expelled inclosed within its membranes. This is of impor- 

 tance. While retained placenta or afterbirth is notoriously common 

 and serious after abortion, it is not likely to occur in early abortion, 

 but only in those cases which have reached or exceeded the sixth or 

 seventh month of pregnancy. The tendency to retained placenta 

 increases with the advancement of pregnancy and reaches its highest 

 degree in cases of premature birth, unless we except those cases which 

 have reached the full period of pregnancy and given birth to living 

 calves, in spite of extensive uterine infection. 



It has been supposed and taught that the firmness of union between 

 the chorion and uterus decreases toward the completion of pregnancy, 

 and that the parts begin to prepare before parturition for the expul- 

 sion of the afterbirth. Observations on the killing floor directly 

 contradict this assumption and show instead that the firmness of 

 adhesion increases constantly up to birth. 



Early in pregnancy the margins of the internal os uteri are thickly 

 studded over with small placentse without marked peduncles. At 

 times they form a complete girdle about the internal os, and come in 

 contact with each other over the os to constitute a broad, flat pla- 

 cental mass 2 to 3 inches across, totally masking the os. However, 

 they are not enduring, and when the fetus has reached a length of 10 

 to 12 inches they begin to become detached and finally disappear. 

 In the process of detachment more or less placental hemorrhage 

 ensues, so that in a large proportion of cases where the fetus is 10 to 

 15 inches long a careful observation of the utero-chorionic space at 

 the internal os reveals a small blood clot, resting usually upon the 

 uterine end of the uterine seal, where it undergoes retrogressive 

 changes. At first bright red, it later becomes black, then fades slowly 

 to a pale yellowish red, to constitute a sticky remnant staining the 

 anterior end of the uterine seal. The amount varies; while usually 

 but a drop or two, it may reach one-half ounce or more. As preg- 

 nancy advances adjacent cotyledons begin to detach about their 

 peripheries and small hemorrhages occur. Whether physiological or 

 pathological, the hemorrhage is suggestive of importance in relation 

 to contagious abortion because at the very point where the abortion 

 exudate commences to form there exists generally an amount of inert 

 blood coagulum to furnish a breeding ground for bacteria, like a blood 

 clot in a wound. 



Another phenomenon of a somewhat similar character is common 

 among the larger, more typical cotyledons. As pregnancy advances 

 43378°— 14 4 



