I go 



THE TRUNK. 



to the rear ; and h^ ab the angle through which they, respectively, turn 

 during an inspiration. We shall then see that the difference of capacity — 

 shown by the difference of area between the shaded oval and the one which 

 circumscribes it — is greatly in favour of the round barrel. If it were possible 

 to have a chest perfectly circular (as in Fig. 178) at the end of an expiration ; 

 the transverse axis of the chest, when the lungs were fully inflated, would 

 exceed in length the vertical axis. 



The second desirable condition — namely, good length of 

 ribs — should, as we have seen, be obtained rather by rotundity 

 than by the distance which the ends of the ribs, respectively, 

 are from each other. Given ribs sufficiently round, we need 

 not trouble ourselves much as to their length, except as 

 reg^ards the farthest back ones, which should be as long^ and 

 as much directed outwards as possible, so as to afford a broad 

 attachment to the diaphragm {see p. 46). It would be easy 

 to prove that the more inclined the ribs are to the rear, the 

 greater will be the difference in capacity of the chest when 

 empty, to what it would be when full of air, and conse- 

 quently the better the breathing power ; but I do not think 

 that it is possible to estimate this inclination with sufficient 

 accuracy to make it a practical guide. My experience leads 

 me to conclude that all useful purposes, in this respect, will be 

 served by satisfying ourselves whether or not the horse under 

 examination is " well-ribbed up." If the last rib be short, fiat, 

 and but little inclined to the rear, the animal will be "slack 

 in the loins," and will most certainly not have as good 

 breathing power as he would have had, if that rib had been 

 long, "springing" well out from the side, and inclined so 

 much to the rear that there would be space only for the ends 

 of two or three fingers between it and the point of the hip. 

 Such a desirable shape would give the utmost width of base 

 to the diaphragm, which is a very important muscle of 



