186 Prof J. N. Langley. On Nerve Endings and on [May 24, 



maximum flexion may not be attained for several minutes. Such a record is 

 given in fig. 8. 



Fig. 8. — Frog. Brain and spinal cord destroyed. A thread was tied to the manus and 

 connected with an unweighted lever, so that flexion of the arm caused a rise of 

 the lever,* 1 c.c. 1 per cent, nicotine injected into the abdominal cavity at the 

 time shown by the signal. Time marked in 10 seconds. 



The tonic contraction is not confined to the muscles of the fore limb. If 

 dilute nicotine (0'05 per cent.) is injected into the bulbus arteriosus, it is 

 seen that all the muscles of the body, except those of the thigh and lower 

 leg, become tonically contracted. The duration, strength, and other features 

 of the contraction vary in different muscles, and in some instances it is 

 accompanied by fibrillar twitching. In the thigh and lower leg muscles 

 there is, so far as can be seen with the eye, twitching only, if the nicotine 

 is sufficiently dilute. Moreover, if instead of injecting nicotine it is applied 

 locally to the muscles (0 - 05 per cent, solution and upwards) local contraction 

 is produced ; thus the numerous extensors and flexors of the toes of the fore 

 and hind limb can be made to contract separately. It may be noted, too, that 

 the rate of contraction of the abdominal muscles is considerably quicker 

 than that of the flexors of the arm. Different muscles, then, show nearly all 

 the possible variations. 



An interesting point is that on applying nicotine to a portion of a muscle 



the tonic contraction occurs in this portion only and does not spread to the rest 



of the muscle. When stronger solutions of nicotine (0 - 5 to 1 per cent.) are 



used, tonic contraction also takes place in the thigh muscles. On application 



to a portion of a muscle, a local wheal, like the ideo-muscular contraction, is 



formed at the place of application. If the sartorius muscle is cut out and 



* It will be noticed that the flexion takes place in a series of small jerks ; the cause of 

 this I have not yet investigated. 



