DISEASES OF THE NERVOUS SYSTEM. 323 



specialization of function in tlie spinal cord, and cispecially 

 in the brain, as elsewhere. 



We may compare the brain and spinal cord to the 

 great collection of central offices of a vast telegraphic sys- 

 tem, with the nerves as the conducting wires, and the 

 nerve-endings as the outlying smaller, less important of- 

 fices of the system. Another useful comparison, espe- 

 cially in understanding the functions of the cord and 

 reflex action, is that of a battery representing the central 

 nerve-cells, and the circuit as completed by the nerves 

 and nerve-endings representing the wires. 



The connection of every part of the body with the 

 central nervous system and with the other regions, so that 

 all the parts constitute a related {co-ordinated) whole, is 

 one of the most important truths to be borne in mind by 

 both physiologist and practitioner. 



The nervous system in the dog is well developed, yet 

 somewhat unstable ; hence functional disease of this part 

 is common. 



Rabies (Hydrophobia).— This is the gravest of all the 

 diseases of the dog, both as regards the canine and human 

 species, since it is invariably fatal, and is common to the 

 dog and many other animals. The disease has been much 

 misunderstood and dreaded by the non-professional por- 

 tion of the public, though it is to the credit of dog-breed- 

 ers that they have generally taken a sensible view of the 

 subject. 



Eabies has been treated at great length in some works, 

 much useless speculation being indulged in up to within 

 recent years, when the illustrious Pasteur put the subject 

 on a more scientific basis. We have still a great deal to 



