218 HEALTH AND DISEASE 



movement, a condition of system which produces a disposition to inflam- 

 matory diseases. The lymphatic temperament, sometimes described as 

 phlegmatic, is exactly the reverse of the sanguine; it is associated with 

 a feeble circulation, a deficiency of red particles in the blood, pallor of 

 the mucous membranes, and coldness of the skin, especially in the ex- 

 tremities, and it predisposes the individual to chronic diseases of a low 

 type. The bilious temperament is probably always connected with a 

 want of activity of the liver and other parts of the digestive organs, which 

 tends to depress the vitality. A nervous temperament is indicated by 

 excitement alternating with depression, both conditions resulting in a 

 predisposition to what are called nervous affections. 



Age has a marked influence in developing or fostering a tendency to 

 special forms of disease. 



It is well known that the foal suffers from diseases to which the 

 state of the organism and the circumstances of its life render it peculiarly 

 susceptible. The young animal is liable to the effects of cold, which in- 

 duces irritation or inflammation of internal organs. Very trifling errors 

 in dieting — in the sensitive state of the digestive canal — cause severe, 

 sometimes fatal, attacks of diarrhoea. The brain is easily excited, and 

 the process of teething increases the liability to various febrile and gastric 

 disorders. 



In advanced age the horse is predisposed to rheumatic affections, 

 stiffness of joints from the increasing density of the ligamentous structure, 

 while the muscular powers are impaired from loss of the true contractile 

 tissue and the increase of fibrous structure, and the steady decrease of 

 the vital powers adds to the predisposition to diseases of a chronic type. 

 It may, however, be affirmed that the influence of the different age 

 periods in the horse in the production of predisposition to disease is not 

 to be compared to the changes which occur in the system of the human 

 subject at different periods in his far longer average life. 



Sex as a predisposing cause of disease relates chiefly to the generative 

 system, and in the lower animals the female is predisposed to affections 

 due to gestation and parturition from winch the male animal is necessarily 

 exempt; but in other respects no important difference has been observed. 

 Mares are not more nor less liable than horses to those affections to which 

 the equine race is prone. 



Occupation is quoted among the predisposing causes of particular 

 diseases in man, and it is surely the case that horses are likewise rendered 

 susceptible to maladies of a kind which are incidental to their occupation, 

 i.e. the kind of work which they are required to perform. It is only 

 necessary to compare the occupation of the hunter with that of the agri- 



