336 THE KIDNEYS. 



warmly clothed, and tlie stable well ventilated, but not cold. Carrots or 

 green meat will be very beneficial. Should the purgmg, when once ex- 

 cited, prove violent, we need not be in any haste to stop it, unless inflam- 

 mation is beginning to be connected with it, or the horse is very weak. 

 The medicine recommended under diarrhoea may then be exhibited. A 

 few shght tonics should be given Avhen the horse is recovering from an 

 attack of jaundice. 



The Spleen is sometimes very extraordinarily enlarged, and has been 

 i-uptured. We are not aware of any means by ■v\hich this may be dis- 

 covered, nor any treatment calculated to afford relicl'. 



THE KIDNEYS. 



The blood contains a great quantity of watery fluid unnecessary for the 

 nutriment or repair of the frame. There likewise mingle with it matters 

 that would be noxious if suffered to accumulate too much. The kidneys 

 are actively employed in separating this fluid, and likeAvise carrying off a 

 substance which constitutes the peculiar ingredient in urine, called the 

 7irea, and consisting principally of that which would be poisonous to the 

 animal. The kidneys are two large oval glandular bodies, placed under 

 the loins, of the shape of a kidney-bean, of immense size. The right 

 kidney is most forward, lying behind the liver ; the left is more backward. 

 A large artery runs to each, carrying not less than a sixth part of the 

 whole of the blood that circulates through the frame. This artery is 

 divided into innumerable little branches most curiously complicated and 

 coiled upon each other, and the blood, traversing these convolutions, has 

 its watery parts, and others the retaining of which would be injurious, 

 separated fi'om it, and, thus separated, passes into a muscular membranous 

 tube connected with the pelvis of each kidney, and is conveyed through 

 them into the bladder. 



This fluid varies materially both in quantity and composition, even 

 during health. There is no animal in which it varies so much as in the 

 horse — there is no organ in that animal so much under oui- command as 

 the kidney ; and no mediciues are so useful, or may be so injurious, as 

 diuretics — not only on account of their febrifuge or sedative effects, but 

 because of the j^ower which they exert. They stimulate the kidneys to 

 separate more aqueovis fluid than they otherwise would do, and thus 

 lessen the quantity of blood which the heart is labouring to circulate 

 tlirough the frame, and also that which is determined or driven to parts 

 already overloaded. The main objects to be accomplished in these diseases 

 is to reduce the force of the circulation, and to calm the violence of ex- 

 citement. Diuretics, by lessening the quantity of blood, are useful 

 assistants in accomplishing these purposes. At the anterior edges of the 

 kidneys are two vascular bodies called the renal capsules, large and of a 

 deep red colour in foetal life, while in maturity they are smaller and 

 lighter in colour : their functions are unknown. 



The horse is subject to effusions of fluid in particular parts. Swelled 

 legs are a disease almost peculiar to him. The ox, the sheep, -the dog, 

 the ass, and even the mule, seldom have it, but it is for the removal of 

 this deposit of fluid in the cellular substance of the legs of the horse that 

 we have recourse to diuretics. The legs of many horses cannot be 

 rendered fine, or kept so, Avithout the use of diuretics ; nor can grease — 

 often connected with these swellings, producing them or caused by them 

 — ^be otherwise subdued. It is on this account that diuretics are ranked 

 among the most useful of veterinary medicines. 



In injudicious hands, however, these medicines ai-e sadly abused. 



