INTRODUCTION. ll 



stimulants, according to the special part which they 

 act upon. 



A Sedative is an agent which diminishes the func- 

 tional activity of an organ, lowers motility, and de- 

 creases the sensation of pain. In this way a soothing 

 influence is exerted on the system. 



Sedatives are divided into two classes, viz., Gen- 

 eral Sedatives and Local Sedatives. 



General Sedatives affect the entire system more 

 or less (this includes narcotics and ansesthetics). 



Local Sedatives affect a part ovi\y — as pulmonary, 

 spinal, nervous, cardiac sedatives, etc. 



Agents Acting on the ITervous System. 



Motor excitants, cerebral excitants, deliriants, mo- 

 tor depressants, cerebral depressants, narcotics, hyp- 

 notics, analgesics or anodynes, anaesthetics, anti-spas- 

 modics. 



Motor Excitants are agents which increase the 

 functional activity of the spinal cord and motor ap- 

 paratus, producing a heightened reflex excitability 

 and disturbances of motility. Large doses produce 

 tetanic convulsions, and the ultimate result is a motor 

 paralysis from over-stimulation. Nux vomica and 

 ignatia with their alkaloids, strychnine and brucine, 

 ergot, and digitalis belong to this class. 



Motor Depressants lower the functional activity 

 of the spinal cord and motor apparatus, and when 

 given in larger doses paralyze these directly. Chief 

 members of this group are ether, chloroform, opium, 

 aconite, chloral, lobelia, and belladonna. 



