19 



ANATOMY OF THE HORN. 



From the various authorities on the subject, the following information has 

 been gathered concerning the anatomy of the horn : 



The outer shell or horn proper is a continuation of the skin or hide, and 

 under the microscope has the appearance of a bundle of pressed hair. lb is 

 moulded upon a central core of bone, which projects from the frontal bone. In 

 the young calf the nucleus of bone inside the rudimentary horn moves freely on 

 the bone of the forehead, adhering and hardening as age advances. This central 

 bone becomes hollowed oat when it passes a certain age, and it is then lined by a 

 delicate membrane, which is the continuation of the membrane that lines 

 the chambers of the nose. The cavity in the horn core is a part of the system of 

 air chambers which serve to lighten the head without altering its size or shape. 

 When the horn is removed the brain is still protected from thi air by an inner 

 plate of bone. The bone of the horn has an exceedingly rough, uneven surface, 

 which holds firmly the fibrous and vascular membrane, known as the 

 matrix of the horn shell. The blood required for the nourishment of the bone 

 is furnished by capillary vessels passing into the bone from the deep layer of the 

 periosteum, and the nerve trunk enters the horn on the inner front near the eye 

 and thence branches off into numerous nerve filaments. There is but little 

 sensibility in the bone, and as there is none in the horn, it follows that it is only 

 in the part, between the bone and the horn that any considerable pain would be 

 caused by an operation upon a healthy animal. No proof can be given of the 

 capacity for suffering contained in the horn nerves. Some veterinarians claim 

 that from the nature of its function and the fact that there is no active process 

 of waste and repair going on, the horn is not likely to be endowed with a great 

 degree of nervous sensibility ; others again emphatically contend that the part 

 is highly sensitive and that the operation is accompanied by the keenest pain that 

 could well be inflicted. The form and length of the horn varies in different 

 animals, and there is also a considerable variation as to the size of the cavity in 



the horn. 



A Microscopic Examination. 



A microscopic examination was made by H. A. McCallum, M.D., Professor 

 Western University, London, Ont., at the request of Mr. E. R. Cameron, of Lon- 

 don. His report reads : 



Dear Sir : — I made a microscopic examination, as requested, of the cow's horn. It is com- 

 paratively nerveless. One bundle enters in front bur. I do not believe its functions to be com- 

 mon sensation or pain, but rather nutrition, locality, temperature and pressure sense. 



The cu'tingof bone is a comparatively painless operation and I cannot think cows suffer 

 during the dehorning operation. 



With reg;tid to dressing the bone after the operation, I should protest against any. The 

 blind spaces would be filled by blood immediately after the cutting, and healing here by "blood 



