6 Veterinary Medicine. 



finally, from impairment of, or separation from the inhibitory 

 centre in the cerebrum. It may be impaired or abolished from 

 degeneration or destruction of any of the tissues just named, or 

 of the conducting nerves which connect them to each other. 



The contraction and closure of the pupil under light is a reflex 

 act from the retina on the optic lobes, etc. , and from these 

 through the motor oculi to the iris. This reflex is lost and the 

 iris fails to contract in : anaesthesia of the retina ; atrophy of the 

 optic nerve ; disease of the optic lobe ; superior (posterior) spinal 

 sclerosis ; disease of the motor oculi ; or disease of the iris. 



The lumbar, reflex is lost in many febrile states in the horse, so 

 that pinching of the loins fails to produce wincing, and this be- 

 comes a test of the active persistence of the disorder. 



Increased Reflex is often noticed when the parts, including 

 the spinal reflex centre, are disconnected from the brain : as in 

 lesions or disease of the cord in front (cephalad) of its reflex cen- 

 tre. Here the cerebral or voluntary inhibition is lost. 



Reflex Tonic Spasm of muscles around a diseased or dislo- 

 cated joint, or of those controlling its action, often affords a val- 

 uable means of diagnosis, the possibility of nervous, muscular 

 and tendinous disease being excluded. 



TROPHIC SYMPTOMS AND DISORDERS. 



Degenerative atrophy, in hsmoglobinuria, laryngeal hemiplegia, neurec- 

 tomy, nerve lesion, brain or cord lesion, lead poisoning, disuse. Dermatitis, 

 ulceration, morbid secretion, polyuria, mellituria, albuminuria, poisonous 

 milk. 



Degenerative Atrophy. From section, disease, atrophy or 

 degeneration of nerves or nerve centres, the muscles, which they 

 normally innervate, waste, often to an extreme degree. As ex- 

 amples of this we see the atrophy of the triceps extensor cruris 

 and other groups in hsemoglobinuria, of the intrinsic laryngeal 

 muscles in roaring, of the muscles supplied in neurectomy, and of 

 groups of muscles in myelitis, broken back, lead paralysis, and 

 scapular muscular atrophy. True to the law of wasting of physi- 

 ologically inert organs, the nerves are atrophied and degenerated 

 and often also the bones, joints and skin. 



