1906.] Special Excitable Substances in Cells. 



175 



Fig. 2.— The same fowl as in fig. 1. Two minutes after injection of 5 milligrammes of 

 nicotine into the jugular vein. The injection caused a gradual and fairly quick 

 extension of the legs, retraction and twisting of the neck, aDd opening of the 

 eyes. In order to show the eyes, the beak was held when taking the photo- 

 graph. The fowl was unfastened throughout, and the injection caused no 

 general movement nor any decrease of the anaesthesia. 



Fig. 3. — The same fowl half an hour after the injection of 5 milligrammes of nicotine. In 

 the interval the fowl had been lifted up to observe the degree of contraction 

 of the muscles, so that the position is probably not exactly the same as in the 

 previous photograph. Most of the muscles still have some tone, more than 

 thej' have in anaesthesia without nicotine ; but the eye muscles are appa- 

 rently in the normal anaesthetic state, for the eye is closed. The eye began to 

 close in about a quarter of an hour. 



The rate of shortening varies with the amount of nicotine. After intra- 

 venous injection of 1 to 5 milligrammes the approximate maximum is not 

 attained for 20 to 30 seconds ; and even with very large amounts the rate is 

 never comparable with that of the rapid twitch which is obtained by 



