THE FORE LIMBS. 83 



and tucked up on botli flanks of course, if lame on 

 both hind legs. In this case, the gas in the bowels 

 may not be proportionately less, unless he is other- 

 wise in bad health, but it is more compressed and 

 pushed forwards, and encroaches upon his breathing 

 area. Some horses have habitually an appearance 

 of less residual gas in their bowels even when 

 in health. This gives their belly an unsightly 

 tucked up appearance, but it is not in itself a blemish* 

 It will occur from overwork and is one of the best 

 indications we can have to stop off work, or 

 moderate it ; because, as we have reason to know, 

 this gas must be present in sufficient quantity to 

 maintain the digestive apparatus, so that it is merely 

 pressed out of its legitimate area by the over-worked 

 abdominal muscles, and presses upon the heart and 

 lungs which causes these organs to work under 

 undue pressure from the rear, and which will almost 

 invariably end in inflammation (pleurisy) of their 

 serous covering, called the pleura, if not stopped ; 

 because the pleura invests the lungs, and turns again 

 upon itself and lines the ribs, and during' breathing 

 the two pleuras have to rub over each other, and if 

 the lungs are unduly pressed upon from behind this 

 friction increases and leads to inflammation. 



72. — The trunk at the top has the back bone 

 running its whole length, and we saw that each bone 

 of the back had a bone sticking up called its spine. 

 We further saw that it was the great lengtli of these 

 spines in the fore part of the back which mainly 



G 2 



