392 PHYSIOLOGY 



other muscles. In sucli a patient therefore walking finally becomes 

 impossible, and, with well -nourished muscles and a motor path which 

 is intact, is condemned to pass the rest of his days in bed. 



THE EFFECT OF POISONS ON THE SPINAL CORD 

 The reflex functions of the spinal cord may be abolished by the 

 same drugs, such as ether, chloral, &c., which abolish conductivity 



LEG :' 



BODY 



prosrhotomc 



*NECK . 

 - turning 



BODY. , 



:>^_ - - opisthotontc 



NECK 



/_ _ . - -\ retraction 



FIG. 174. Diagram by Sherrington to show influence of tetanus toxin on the 



response to excitation of the motor area of the cortex in the monkey. 

 A, normal animal. B, after poisoning with tetanus. F and / = flexion of 

 leg and arm respectively. E and e signify extension. < signifies opening of 

 mouth ; = signifies closing of mouth. 



in a nerve fibre. The central effect of these drugs is obtained with 

 much smaller concentrations than is the case with the peripheral 

 nerves and is the cause of their anaesthetic effect. 



More interesting from the point of view of the physiologist is the 

 action of such a drug as strychnine, or the somewhat similar action of 



