274 A Manual of Veterinary Physiology. 



formed by touching the skin of the body with an acid. 

 The animal endeavours to wipe the acid away with the 

 leg nearest to the injury ; and if this leg be secured 

 the opposite one is used for the same purpose. We see 

 nothing so marked as this in the higher animals, though 

 very characteristic reflex actions occur in the dog after 

 division of the cord. It is certain that in the horse, for 

 example, severe injury to the cord may not immediately 

 cause entire loss of motion, though sensation be lost. I 

 have known a horse walk some distance after a comminuted 

 fracture of the dentata, and another to walk a short dis- 

 tance and stand a considerable time, and even to kick, after 

 a fracture of the sixth dorsal vertebra. There can be no 

 doubt, I think, that the spinal reflexes in the larger animals 

 are by no means so well marked as in the dog or in the 

 frog. 



The muscle and tendon reflexes, so well known in the 

 human subject, have not, so far as I am aware, been studied 

 in the herbivora: nor do I know whether their existence 

 has been demonstrated, if, perhaps, I except the immediate 

 lifting up of the foot, which generally follows pressure on 

 the so-called ' chestnut ' found on the inside of the fore- arm 

 of the horse. 



A controlling influence may be exercised over certain 

 reflex acts in the human subject, which are the outcome of 

 moral control, and so have no counterpart in veterinary 

 physiology. 



Under the influence of tetanus and the action of strychnia, 

 the reflex centres in the cord are so easily excited that even 

 a slight noise is sufficient to produce those purposeless 

 muscular movements termed convulsions. 



Centres in the Cord. — Certain centres exist in the spinal 

 cord for the performance of functions, some of which are 

 partly under the control of the will, whilst the majority are 

 not. It is quite possible for the centres to act by them- 

 selves, but under ordinary circumstances they are controlled 

 by higher centres in the medulla. 



The cilio-spinal centre has for its function the dilatation 



