CHAPTER VIII. 



THE NERVOUS SYSTEM. 



Fortunately for the stockman and the veterinarian, 

 farm stock do not suffer from "nerves", such attacks 

 occurring at inconvenient times, although the domesti- 

 cated animals are very easily frightened and certain ani- 

 mals are sometimes irritable, it is as a rule in the latter 

 case especially modified or cured by plenty of work. 

 The organs going to make up this system and their func- 

 tions, therefore, will only receive a brief consideration. 

 The brain, spinal cord and the nerve fibres make up the 

 nervous system, which has the faculty of receiving and 

 interpreting impressions, more or less under the control 

 of the animal; it also has the regulating of the vital 

 functions, such as milk secretion, bowel movements, the 

 heart's action, etc., which are not under the direct con- 

 trol of the animal. In order to render the study of the 

 nervous system easier we divide it into (a) cerebro- spinal 

 and (b) sympathetic systems. The first division (a), 

 which is made up of the brain, composed of four parts, 

 the spinal cord, the nerves originating from the brain, 

 and the chain originating from the spinal cord. The 

 nerves of the first division have been termed nerves of 

 animal life as distinguished from those of the second 

 division (b), termed nerves of organic life. Nerve tissue 

 is made up of white and grey matter. Nerves consist of 

 bundles of fine fibres enclosed in a sheath; along the 



