14 VETERIXARY MATERIA MEDICA. 



Chief Local Ancesthetics : Application of extreme 

 cold, ice, ether spraj', cocaine, carbolic acid, creo- 

 sote, hydrocyanic acid, and oil of turpentine. 

 . Antispasmodics are agents which relieve or pre- 

 vent spasms of voluntary or involuntary muscle in 

 any part of the organism. Their specific modes of 

 action are classed in five divisions : 



1. By tonic stimulation of nerve centres, coordina- 

 tion, and circulation — as alcohol, ether, camphor. 



2. By direct depression of the motor centres — as 

 amyl nitrite and the bromides. 



3. By paralyzing the end organs of the vasomotor 

 nerves — as menthol. 



4. By stimulation of the muscular fibres of the 

 intestines to expel gases and flatus — as valerian, asa- 

 foetida, and the aromatic oils. 



5. By direct depression of the vital functions — as 

 aconite, lobelia, hellebore, and prussic acid. 



Coordination of Movement or maintenance of 

 the equilibrium. The power which controls the ac- 

 tions of the locomotory apparatus is disturbed by a 

 certain class of drugs, especially alcohol. This func- 

 tion is governed by the cerebellum, and in diseases 

 affecting that part of the brain there is a lack of co- 

 ordination. 



Agents Affecting the Organs of Special 



Sense. 



Mydriatics are agents which cause dilatation of 

 the pupil of the eye. Some act only when applied 

 locally, while others act only when taken internally. 



