DISEASES OF THE GENERATIVE ORGANS. 165 



milking. This state of things is present in many old dairy farms, from 

 which the mineral matters of the surface soil have been sold off in the 

 milk or cheese for generations and no return has been made in food 

 or manure purchased. Here is the craving of an imperative need, and 

 if it is not supplied the health of the cow suffers and the life of the 

 fetus may be sacrificed. 



Among other causes of abortion must be named the death or the vari- 

 ous illnesses of the fetus, which are about as numerous as those of the 

 adult ; the slipping of a young fetus through a loop in the navel string 

 so as to tie a knot which will tighten later and interrupt the flow of 

 blood with fatal effect, and the twisting of the navel string by the 

 turning of the fetus until little or no blood can flow through the con- 

 torted cord. There is in addition a series of diseases of the mucous 

 membrane of the womb, and of the fetal membranes (inflammation, 

 effusion of blood, detachment of the membranes from the womb, fatty 

 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. 



CAUSE OF CONTAGIOUS ABORTION. 



"While any one of the above conditions may concur with the con- 

 tagious principle in precipitating an epizootic of abortion, yet it is 

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

 perpetuated 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 contagion. 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 considerable 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, these latter invariably aborted within a month. So Roloff 

 relates that in two large stables at Erfurt, without any direct inter- 

 communication, but filled with cows fed and managed in precisely 



