Hereditary Diseases of Cattle. 
77 
merous. These manifest, however, the same general characters 
as in the horse, and depend upon similar abnormal conditions of 
form and texture. They often cronsist in a vitiated state of the 
system, and are generally of a chronic character, aggravated in 
their nature, didicult of treatment, and very uncertain of cure. 
We shall here notice the more important hereditary diseases 
of cattle, as diarrha>a, rheumatism, scrofula, consumption, dysen- 
tery, malignant tumours, and the affections depending on a ple- 
thoric state of body. 
Undue heat, insufficient quantity and bad quality of food, are 
the most common causes of diarrha'a ; but such causes affect 
some animals more speedily and powerfully than others, showing 
a variety of predisposition to the disease. The animals most 
subject to it are generally distinguished by a narrow carcase, 
weak loins, flat ribs, and a coarse appearance about the root of 
the tail. In such subjects the intestines are very irritable : 
purging is induced by the most trifling cause, and, once excited, 
is arrested with difficulty. But diarrhoea, although often very 
troublesome, is not a dangerous complaint ; it is, in most cases, 
merely a natural efTort to dislodge and carry away some irritant 
from the intestinal canal, to effect which a large quantity of fluid 
is poured out from the mucous surface of the intestines, and the 
peristaltic or worm-like motion of the canal increased, causing 
evacuation of the faeces in a liquid fcwm and more frequently 
than usu.-vl. But there is not necessarily any pain, straining, or 
fever. Blood may sometimes be passed, but, unless this symp- 
tom be accompanied by fever, there is no cause for alarm. In 
simple diarrhoea the appetite and rumination are not impaired, 
and circulation and respiration are perfectly normal. 
The rheumatic diathesis is not uncommon amongst cattle. It 
chiefly affects animals descended from stock which have been 
affected by rheumatism, and will even appear in cattle carefully 
protected from cold and damp and other exciting causes of the 
disease ; thus affording sufficient proof of its hereditary nature. 
The disease presents itself under several different forms. In 
all, however, it manifests those general characters distinctive 
of rheumatic inflammation which we have already noticed 
Avhen treating of this class of diseases in the horse. It affects 
fibrous and serous tissues, is very inconstant and migratory in 
its seat, and is usually attended by a great degree of acute fever, 
as evidenced by a full, hard, and resisting pulse. There are 
some peculiarities which distinguish the rheumatism of horses 
from that of cattle ; in the former it does not usually occur as an 
idiopathic disease, but commonly as a sequel to other diseases ; 
in the latter it often occurs independently of any other disease, 
and, when so occurring, is usually very obstinate in its nature 
