DISEASES Of THE OX AND SHEEP. 667 



about five in a thousand. Amongst the chief and, perhaps, most 

 preventable of the remaining causes are the imperfections in the 

 character of the blood supplied to the offspring during its foetal 

 life, and those alterations of the nervous system of the mother 

 which alter the calibre of the vessels supplied to the foetus to 

 such an extent as to cause an insuflBcient or intermittent blood- 

 supply. No doubt the alterations in the blood-supply are due to 

 some imperfection of diet, including both food and water. Again, 

 virulent germs may be introduced from without, or diseased pro- 

 ducts may be elaborated within. 



Abortion may also be brought about by a too sudden ingestion 

 of rich food, by sudden alterations in the food-supply, by any 

 cause which interferes with the assimilation of food, by a sudden 

 change from rich to poor keep, or, on the contrary, from poor to 

 rich food — as, for instance in spring-time, when the vegetation 

 is luxuriant, or by the use of food which is too highly nitro- 

 genised, whether artificial or natural. Again, in dry weather, 

 the sources of water-supply may be dried up, or the water may be 

 contaminated with sewage material, coming either from badly- 

 managed drainage or more especially by the presence of decom- 

 posing carcases, blood, or other animal matter. A prominent 

 cause of abortion is the ingestion of herbage grown under 

 circumstances of excessive moisture in low-lying, damp, marshy, 

 grounds, which thereby, perhaps, have a tendency to become 

 ergotised. At any rate, some persons suppose that the growth 

 of ergot near the seeds of grasses and cereals may be promoted 

 by undue moisture and heat. Hence care should be taken during 

 those seasons that the herbage is free from ergot, before it is 

 supplied to animals. If there is much ergot in a pasture, all the 

 cows in-calf should be taken oflF. It ought to be well known on 

 every farm, as a rule, that the more naturally any animal is kept 

 during its period of pregnancy, the less are the chances of it 

 aborting. Moreover, at times, abortion may, so to say, assume an 

 epizootic form. This may possibly be brought about in some 

 cases by unhealthy seasons, or it may, perhaps, be due to faulty 

 management of the food-supply throughout a large number of 

 animals. Instances, however, have been known when abortion 

 has assumed a contagious character. This may, in our opinion, 

 be explained on the theory that a specific fever of a mild 

 character may be transmitted from dam to dam. This may be 



