CHAPTER XV. 



THE NERVOUS SYSTEM. 



From the fact that the nervous system only occupies a very 

 subordinate position in veterinary medicine and surgery, 

 and also that in the lower animals its functions, so far as 

 the brain is concerned, are so immeasurably inferior to that 

 of man, I do not purpose giving more than an outline of 

 the physiology of the parts concerned so far as it has been 

 ascertained. 



The physiology of the nervous system has principally 

 been worked out on frogs, rabbits, dogs, and monkeys. 

 We have no evidence that the various tracks found in 

 the spinal cord of man and dogs exist in the herbivora, 

 though there can be no doubt that some, or perhaps 

 even all, are present ; but the inquiry on dogs and rabbits, 

 which have yielded such fruitful results in determining 

 the paths in the spinal cord, have not been experi- 

 mentally applied to the horse and other large animals, and 

 there are no degenerative diseases of the cord, as in man, 

 pointing to the existence of definite tracks, so that we can 

 only assume the existence of much with which we have to 

 deal. The same may be said of the motor centres in the 

 cerebrum, the knowledge of which is calculated to revolu- 

 tionize brain surgery in the human subject. Motor areas, 

 no doubt, exist in herbivora, but we have no exact evidence 

 of their position, and even if we possessed this knowledge, 

 could not probably turn it as yet to any useful advantage. 



The nervous system is widely distributed throughout the 

 body ; there are but few places where no nerves have been 



