SUPERIOR FACE OF THE BODY. 131 



rior. More recently, our iearned colleague, M. Neumann,^ has, in a 

 full review of this subject, endeavored to oifer diverse criticisms on 

 certain views which we supported on this point in our first edition. 

 These criticisms have induced us to make a careful revision of this part 

 of our book, and we have conducted numerous experiments, the results 

 of which are given in this edition. We are convinced that the diver- 

 gence from our opinion regarding the direction of the croup, held by some 

 writers, is much less reasonable than our critics imagine. They do not 

 sufficiently consider the sources of error, and the compensations and 

 exigencies demanded by the nature of the work which the animal must 

 perform. Very often qualities or defects which belong to other elements 

 of the conformation are attributed to the direction of the croup ; finally, 

 it is common to see persons who choose as a standard of excellence such 

 or such an inclination which has given good results in some instances, 

 without reflecting that different purposes also require peculiar anatomical 

 conditions, which endow the mechanism with a peculiar aptitude. 



The discussion into which we now enter will furnish the proof of 

 what we have said. 



First, how is the direction of the croup manifested ? 



Certain writers .think, incorrectly, that it is indicated by a curve on 

 the median line of the body extending from the termination of the 

 loins to the origin of the tail. This line denotes only the degree of 

 convexity of the sacral spine and the curvature of the sacrum. It is 

 altogether independent of the general direction of the coxse, and 

 influences but little the form of the region. 



The axis of the croup, in our opinion, corresponds almost exactly 

 with a line uniting the angle of the haunch to the point of the ischium 

 and passing some distance above the coxo-femoral articulation ; we will 

 call it the ilio-ischial line. 



We are prepared to assert that the direction of this line depends 

 upon two principles, as follows : 



1st. It may depend upon the dimension of the ilio-ischial angle. 



2d. It may depend upon the more or less inclined position of the 

 coxse without variation in its ang-le. 



a. Influence of the Dimension of the Ilio-ischial Angle. 

 — Two causes are capable of modifying the size of this angle ; they 

 may act alone or simultaneously. It may be the inclination of the 

 ilium alone which varies, or that of the ischium, or, finally, that of both, 

 which may vary at the same time. 



Let us examine each of these cases in particular. 



1 G. Neumann, Sur la direction de la croupe ; in Revue v6t^rinaire, 1887, p. 521. 



