PRACTICAL PHYSIOLOGY 35 



trodes directly to them. The muscles of the 

 poisoned limb react like those of the normal limb, 

 but the liminal stimulation 1 is greater. Determine 

 at what distance of the secondary coil from the 

 primary a response is obtained in each case. 



The conclusion is that neither the nerve fibres, 

 sensory and motor, nor the nerve centres, nor the 

 muscular fibres are affected, but that the poison has 

 produced paralysis by severing the connection 

 between the motor nerve fibres and the muscle 

 fibres, probably at the end-plates. 



Muscle wave. Separate the adductor muscles 

 (gracilis and semimembranosus ; see Figs. 23, 24) 

 of a frog's leg (which has been poisoned with curari 

 so as to eliminate the intramuscular nerves) from the 

 remaining thigh muscles, leaving their attachments 

 to the tibia. Cut this bone through just below 

 these attachments, and also sever the tibia from 

 the femur at the knee joint. It is then easy to 

 effect the separation of the muscles up to their 

 iliac attachments ; a small fragment of the ilium 

 may be cut away and removed along with them. 

 Tie a thread to the tibial and another to the iliac 

 attachment, stretch the muscular mass lightly be- 

 tween these threads, and fasten the threads by a 

 couple of pins to the frog-cork. Allow a light 

 muscle-lever to rest across the muscles near one 

 end. The movements of the lever are recorded 

 upon a rapidly revolving drum, and curves are to 

 be obtained of the swelling of the muscle during 



'The stimulation which is just effective/.*., just produces a 

 response. 



