DRUGS ACTING ON THE NERVOUS SYSTEM 41 



If recovery should follow the paralytic stage, the bodily 

 functions return in the reverse order to that in which they 

 were lost ; ^'.e., the lower vital functions first appear, followed 

 finally by the higher cerebral functions. 



Uses. — Anaesthetics are employed in surgical operations 

 to prevent pain and struggling; in obstetrical operations 

 and in the reduction of fractures, dislocations and hernia, to 

 secure complete muscular relaxation ; to overcome spasms 

 and convulsions resulting from disease or poisons ; to arrest 

 severe pain in colic ; and finally to destroy aged or sick and 

 useless animals. 



For fuller details see Anaesthesia (p. 281). 



(c) Drugs acting on the cortical motor centres of the brain. 



(1) DRUGS STIMULATING THE MOTOR CENTRES. 



Strychnine Physostigmine 



Atropine 



(2) DRUGS DEPRESSING THE MOTOR CENTRES. 



The Bromides Alcohol 



Chloral Anaesthetics 



The action of drugs on the cerebral cortical centres has 

 been found by comparing the local effect of electrical stim- 

 ulation before and after the internal use of drugs. 



Uses. — The drugs depressing the cortical motor area of 

 the brain are valuable in convulsions and spasmodic disorders 

 and in motor excitement, particularly in epileptiform 

 convulsions of dogs. 



II. — Drugs Acting on the Spinal Cord. 



The functions of the cord consist in the conduction of 

 sensory impulses forward to the brain and of motor impulses 

 backward to the muscles; in the origination of nervous 

 force in centres controlling certain functions (sexual, sweat- 

 ing, etc.) ; and in reflex action by which the cord transmits 

 impulses from sensory to motor tract of the same side of 

 the body, or laterally, from sensory to motor columns on 

 opposite sides. 



