HEREDITARY DISEASES OF HORSES. 
639 
pulse. Sometimes, as in lumbago in the human subject, it 
affects the muscles of the back and loins, causing stiffness, 
tenderness, and pain, which are especially evinced on moving 
or turning the animal. These rheumatic affections are very 
readily produced in predisposed subjects by exposure to rain 
and cold, especially when accompanied by over-heating or 
exhaustion. Rheumatism sometimes occurs in horses as a 
prominent symptom of that epizootic affection which usually 
receives the much-abused title of influenza. In such cases 
the rheumatism is of a somewhat more sub-acute or chronic 
character than common, and is accompanied by that low 
debilitating fever so often the concomitant of epizootic 
maladies. It usually affects all parts of the body susceptible 
of the rheumatic inflammation, is attended particularly by 
those symptoms which indicate disease of the heart and 
pericardium, as an irregular intermittent pulse, and often 
terminates fatally by effusions into the pleurae or pericardium, 
thus causing death by arresting the motions of the heart. 
As we shall have again to notice rheumatic diseases when 
speaking of cattle, we leave the subject for the present, and 
proceed to the scrofulous or strumous inflammation. 
The scrofulous diathesis , or constitution, is not uncommon 
amongst horses. It assumes many degrees of intensity, and 
predisposes to many diseases. It is most apt to discover 
itself in horses with narrow chests, large flat sides, weak 
loins, soft flabby muscular systems, soft thin skins, fine silky 
hair, large badly-proportioned limbs, and large weak joints, 
and in those in which digestion is often impaired, excretion 
irregular, and circulation weak and easily accelerated. In 
an animal affected by scrofula the blood is in an abnormal con- 
dition. There is an alteration in the relative quantity and 
quality of its various constituents, consisting chiefly in a di- 
minution of the red corpuscles, and an excess of fibrine, 
which is besides in a less elaborated state than usual ; tuber- 
cular deposits are also found in various parts of the body. 
This alteration in the healthy quantity and quality of the albu- 
minous ingredients of the blood, and in the integrity of the 
various tissues, is transmitted from the parent to the off- 
spring ; and, in proportion to the amount of deviation from 
the normal state, constitutes a scrofulous diathesis more or 
less decided. The diathesis is strikingly hereditary,* often 
* Dr. Watson, in his admirable * Lectures on the Principles and Practice of 
Physic/ thus speaks of the hereditary nature of this affectiop • — “ In a former 
lecture/' says he, “ I mentioned scrofula as one of those distempers the here- 
ditary tendency to which is indisputable. The scrofulous diathesis is hereditary: 
and sometimes scrofulous disease is so too. I have seen lungs, taken from the 
body of a foetus, stuffed with tubercles. There were some fine examples of this 
