190 DISEASES OF CATTLE. 



or other degenerations, etc.), which interfere with the supply of blood 

 to the fetus or change its quality so that death is the natural result, 

 followed by abortion. 



CONTAGIOUS ABOKTIOX ITS CAUSK. 



While any one of the above conditions may concur with the conta- 

 gious principle in precipitating an epizootic of abortion, yet it is only 

 by reason of the contagium that the disease can be indefinitely perpct 

 uated and transferred from herd to herd. When an aborting cow is 

 placed in a herd that has hitherto been healthy, and shortly afterwards 

 miscarriage becomes prevalent in that herd and continues year after 

 year, in spite of the fact that all the other conditions of life in that herd 

 remain the same as before, it is manifest that the result is due to con- 

 tagion. When a bull, living in a healthy herd, has been allowed to 

 serve an aborting cow, or a cow from an aborting herd, and when the 

 members of his own herd, subsequently served by him abort in consid- 

 erable numbers, contagion may be safely inferred. Mere living in the 

 same pasture or building does not convey the infection. Cows brought 

 into the aborting herd in advanced pregnancy carry their calves to the 

 full time. But cows served by the infected bull, or that have had the 

 infection conveyed by the tongue or tail of other animals, or by their 

 own, or that have had the external genitals brought in contact with 

 wall, fence, rubbing post, litter, or floor previously soiled by the infected 

 animals, will be liable to suffer. The Scottish abortion committee found 

 that when healthy, pregnant cows merely stood with or near aborting 

 cows they escaped, but when a piece of cotton wool lodged for twenty 

 minutes in the vagina of the aborting cow was afterwards inserted into 

 the vagina of a healthy, pregnant cow or sheep, the latter invariably 

 aborted within a month. So Roloff relates that in two large stables at 

 Erfurt, without any direct intercommunication, but filled with cows fed 

 and managed in precisely the same way, abortion prevailed for years in 

 the one, while not a single case occurred in the oth^er. Galtier finds 

 that the virus from the aborting cow causes abortions in the sow, ewe, 

 goat, rabbit, and guinea-pig ; and that if it has been intensified by 

 passing through either of the two last-named animals, it will affect 

 also the mare, bitch, and cat. 



The precise germs or germ causing abortion have not yet been demon- 

 strated beyond question. Twenty years ago Franck, of Munich, drew 

 attention to a chain form of cells (Leptotlirix vaginalis) as the efficient 

 raiise. The Scottish Commission have isolated in gelatin cultures five 

 different bacteria obtained from the vaginal mucus of the aborting cow, 

 arnl Nocard, of Alfort, speaks of a germ existing abundantly between 

 the womb and fetal membranes of aborting cows which was never found 

 in the healthy. 



Symptoms of abortion. In the first two or three months of pregnancy 

 no symptoms may have been observed, and unless the aborted product 



