THE MECHANISM OF CO-ORDINATED MOVEMENTS 347 



nourished muscles and a motor path which is intact, he 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 in a nerve 

 fibre. The central effect of these drugs is obtained with much smaller con- 



LEG :' 



BODY . 



prosrhotonic 



NECK . 

 turning 



BODY. , 

 ^^.- - op/sfnofonic 



NECK 



refraction 



FACE -// 



FIG. 173. 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. 



centrations than is the case with the peripheral nerves. Hence their value 

 as general anaesthetics. 



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 the toxin 

 formed by the tetanus bacillus. If a small dose of strychnine be injected 

 into a spinal frog, after a short period of heightened irritability the slightest 

 stimulus applied to the surface will cause spasms, which may affect every 



