238 LAAIKNESS. 



first year of the animal's life, and it may not always be viewed 

 as " congenital," Grazing on very bare pastures is apt to cause 

 it, more especially if the foal be short in the neck, or when so 

 formed that he has to bend over on his fore limbs considerably 

 before he is able to obtain his bite of grass. Continuance in this 

 position for a long time each day causes a weakening and arrest- 

 ment of development of the extensor muscles, whilst at the samo 

 time the flexors called into action are excited to increased 

 development. We have thus, concomitantly, atrophy of the 

 extensors and hypertrophy of the flexors. 



Mr, Armatage recommends the continued application of 

 mild blisters to the anterior region of the arm, to excite the 

 exudation of plastic material and the development of the 

 exudate into muscular fibre, and, by bringing more blood to 

 the part, to increase its tone and power, and elevate its func- 

 tional activity. 



A horse may be lame from excess of tonicity in the muscles 

 of a limb, accompanied by much pain, as in cramp, which renders 

 him for the time being dead lame. 



In other cases lameness may be due to disease in the blood- 

 vessels of the limb or their parent trunks. For example, most 

 extreme lameness is manifested in limbs when their " arteries 

 of supply" become plugged by thrombi. Cases of this kind have 

 occurred in my own practice, whore the horse became dread- 

 fully lame, and exhibited symptoms of great agony when- 

 ever put to work, while in the stable no signs of pain were 

 present ; but when he had worked in the carriage for about 500 

 yards, he would show signs of weakness in one hind limb, 

 commence to sweat, and finally become immoveable with pain. 

 After a short period of repose, these symptoms would dis- 

 appear, but appear again if any attempt was made to work 

 him. 



In addition to pain and lameness, the limb was deathly cold 

 to the touch, and upon a post mortem examination being made, 

 the external iliac artery of that side was found nearly oblite- 

 rated by a deposition of fibrine. 



In the detection of th^ lame limb, the following rules may be 

 laid down for the guidance of the young practitioner : — When 

 tue lame limb comes to the ground during progression the 

 animal suddenly elevates that side of his body and drops the 



