800 THE HEART. 



doubt that amongst all horses, especiallj those last mentioned, broken-wind 

 is to a certain .extent hereditary. 



Is there any cure for broken-wind ? None ! no medical skill can repair 

 the broken-do^vn structure of the lungs. 



If, however, we cannot cure, we may in some degree palliate broken- 

 wind : and, first of all, we miist attend carefully to the feeding. The food 

 should lie in little compass, — plenty of oats and split beans, with a mode- 

 rate allowance of chaff. Hay is olijectionable, from the rapidity with which 

 it is U-Sually devoured, and the stomach overdistended. Water should be 

 given in moderate quantities, but the horse should not be suffered to drink 

 as ranch as he likes until the day's work is over. Green meat will always 

 be serviceable. Carrots are particularly useful ; they are readily digested, 

 and appear to have a peculiarly beneficial effect on the respiratory system. 



It is from the want of proper attention to the feeding that many horses 

 become broken- winded even in the straw-yard. There is little nu.triment 

 in the provender which they find there ; and in order to obtain enough 

 for the support of life, they are compelled to keep the stomach constantly 

 full, and pressing upon the lungs. It has been the same when they have 

 been turned out in coarse and innutritive pasturage. The stomach was 

 perpetually gorged, and the habitual jjressure on the lungs cramped and 

 confined their action, and inevitably ruptured the cells Avhen the horse 

 gambolled Avith his companions, or was wantonly driven about. 



Next in importance stands exercise. The broken- winded horse should 

 not stand idle in the stable a single day. It is almost incredible how 

 much may be done by attention to food and exercise. The broken-^Wnded 

 horse may thus be rendered comfortable to hhnself, and no gi-eat nuisance 

 to his owner ; but inattention to feeding, or one hard journey, — the 

 animal unprepared, and the stomach full, — may bring on inflammation, 

 congestion, and death. Occasional physic, or alterative medicine, will 

 often give considerable relief. 



THE HEART. 



The heart is placed between a doubling of the pleura — the mediastinum, 

 by means of which it is supported in its natural situation, and all danger- 

 ous friction between these important organs is avoided. It is also sur- 

 rounded by a membrane or bag of its own, called the ■pericardium^ whose 

 office is of a similar nature. By means of the heart the blood is circulated 

 through the frame. 



It is composed of four cavities — two above, called auricles, from their 

 supposed resemblance to the ear of a dog ; and two below, termed ventricles, 

 occupying the substance of the heart. In point of fact, there are two 

 hearts — the one on the left side unpelliiig the blood through the frame, 

 the other on the right side through the pulmonary system ; but, united 

 in the manner in which they are, their junction contributes to their 

 mutual strength, and both circulations are carried on at the same time. 



The first is the arterial cii'culation. No function can be discharged, 

 life ccnnot exist, without the presence of arterial blood. The left ventricle 

 that contains it contracts, and by the power of that contraction, aided by 

 other means, which the limits of our work will not permit us to describe, 

 the blood is driven through the whole arterial circulation — the capillary 

 vessels and the veins— and returns again to the heart, but to the right 

 ventricle. The other division of this viscus is likewise employed in cir- 

 culating the blood thus conveyed to it, but not the same fluid which was 

 contained in the left ventricle. It has gradually lost its vital power as it 

 has passed along ; it has changed from a bright to a dark red, and from a 

 vitil to a poisonous fluid. Ere it can again convey the jorinciple of nutri- 



