ANTERIOR MEMBER. 205 



applied vertically or obliquely upon the sides of the thorax, has a 

 tendency of itself to elevate or to lower the centre of gravity by 

 augmenting or by diminishing the total length of the member in this 

 proportion, at those times when the anterior extremity of the body is 

 'being displaced. The centre of gravity, however, in order to be in 

 accordance with the laws of equilibrium and of speed, should have a 

 favorable position and not be too elevated. Furthermore, a shoulder 

 can profit by its length only when it is correspondingly inclined ; 

 otherwise, the reactions will be hard and the animal without action in 

 consequence of the defective orientation of the superior angles of the 

 member. 



There is an idea, very generally prevalent, that, in the draught- 

 horse, marked length of the shoulder constitutes a defect rather than 

 an advantage. This is an error which the partisans of such a theory 

 could very easily demonstrate by making some practical measurements 

 upon the very best specimens of draught-horses. In them, also, the 

 head is the measurement of the shoulder. The great length of this 

 region is in all cases, in our opinion, the first and most important ele- 

 ment of its beauty and perfection. There are, without doubt, draught- 

 horses with short shoulders capable, nevertheless, of very effective 

 service, and the disadvantages of this defect in them do not have the 

 same importance which they would have in the race-horse. In the 

 draught-horse, amplitude of the movements is secondary ; the essen- 

 tial qualities reside in the resistance which can be overcome by the 

 power of his muscles and the proper incidence of their insertions. 

 To say that the length of the scapula and its muscles, in these slow- 

 moving animals, is defective and incompatible with the power of the 

 muscles, is to advance a principle which is entirely incorrect and with- 

 out proof. 



2. Length of the Shoulder in Relation with the Arm. 

 On general principles the shoulder and the arm should be long abso- 

 lutely, in order to be favorable to velocity ; but, with the same total 

 length of these two segments, it is necessary that the former be long 

 and the latter short. This becomes apparent from the following dem- 

 onstration : 



Let us represent (Fig. 58) the two shoulders, AB, AB / , and the two arms, 

 CD, CD', having the same reciprocal inclination and giving the same total sum, 

 AB+ CD being equal to AB'+ C'D' by hypothesis. 



AC 1 



From our estimations, the relation - is equal to - ; we have preserved the 



AD o 



A C / 



same relation for - -, the conditions in both cases being therefore comparable. 

 AD 



