560 journal of Agriculture. [10 Sept.. 1910. 



dairying industry, although, fortunately, the disease is now completely 

 under control there, and now does little damage. 



Animals Affected. 



The disease, as a contagious disease, chiefly affects cows, although 

 outbreaks are noted from time to time amongst sheep, and occasionally 

 epidemics of abortion have been recorded in studs of mares. As to whether 

 it is the same microbe that produces the disease in each of these animals 

 is not yet known, but experiments have proved that the bacillus which 

 causes bovine abortion will actually produce the same disea.se in sheep. 



Symptoms. 



The symptoms manifested by an animal about to abort are extremely 

 slight ami indefinite in the majority of ca.ses. Often none whatever are 

 manifested, and this may even apply to experimental cases, for fre- 

 quently the only evidence of the trouble is the presence of the aborted 

 foetus found lying behind the mother in the morning. At other times, 

 however, a general uneasiness may be observed, there m.ay be a rapid 

 swelling of the udder, a slight discharge of slimy, sometimes blood-tinged 

 material from the vulva, but generally nothing more definite. As a rule, 

 the owner of animals which are not housed is made aware that a case of 

 abortion has occurred by finding the immature foetus on the ground, or by 

 noticing a cow with an unexpected flow of milk and .some discharge from 

 behind, staining the tail. The general condition of the animal is .so little 

 disturbed that otherwise she remains quite normal. The reason of this is 

 not difficult to find. If an animal which has just aborted be slaughtered, 

 and carefully examined, it will be .seen that the only disease changes 

 which have occurred are in the lining membrane of the womb. Even then 

 one only observes a small quantity — sometimes so small as to be readily 

 overlooked — of a !ight-browni.sh or dark coloured sticky semi-fluid material. 

 Sometimes the "cotyledons" or raised areas mav be pulpy looking and 

 yellowish, but this is not always to be ob.served. 



Shortly, the conditions that exist are simply due to a slight catarrhal 

 inflammation of the womb. Even the aborted foetus is usually quite normal, 

 as are the covering membranes. Occasionally, however, the foetus may 

 be partially mummified, due to the fact that it has been dead some time 

 before expulsion. 



Methods of Infection. 



T\\n microbe which causes the disease is practically only to be found 

 in the sticky exudate which covers the inside of the womb and the surface 

 of the membranes or cleansings. It will therefore be seen that the chief 

 means whereby the disease is spread are the discharge which is apt to be 

 persistent for some time after the cow has aborted, and the [jortions of the 

 abortion, particularly the cleansings. It has been proved that the microbe 

 may retain its vitality and virulence for a period of six months, provided 

 it is kept moist and away from the sunlight. As the membranes may lie 

 upon the ground in a shady place and not become thoroughly dried, it is 

 obvious that unless they are discovered and destroyed they may remain 

 for a considerable period a source of further infection. Under experi- 

 mental conditions it has been proved that one very certain means whereby 

 the germ may gain entrance into the system is along with the food supply, 

 and as cows are very prone to chew all sorts of material, and particularly 

 liable to congregate where any blood-stained matter is to be found, the 

 danger of leaving the membranes undestroyed becomes doubly obvious. 



