BY H. G. CHAPMAN. 



301 



It may be concluded that this effect of strychnine is manifested 

 on the receptive substance between the nerve fibres and the 

 muscle fibres. The direct irritability of the muscle fibres is pro- 

 bably unaffected. In other words, from this point of view, Hyla 

 reacts similarly to strychnine and curare.* 



Further corroboration of this opinion was obtained by experi- 

 ments conducted for me in vitro by Messrs. Foy, Schmidt, and 

 Macintosh, students in medicine. For their assistance I wish to 

 express my thanks. 



Nerve-muscle preparations were dissected from frogs in pairs 

 and immersed in solutions of strychnine in such a way that the 

 nerve of one preparation and the muscle of the other preparation 

 were suspended in the solution. The stimulus which just caused 

 a contraction when applied to each nerve and each muscle was 

 recorded at appropriate intervals. Faradaic currents were 

 employed from a standard inductorium and one bichromate cell. 



The first series consisted of eight experiments with a solution 

 of 1 part of strychnine in 10,000 parts of normal saline solution. 

 About 5 c.c. of this solution were used in each experiment. The 

 abridged results of one such experiment are recorded in Table iv. 



Table iv. 

 The figures represent the distance in cm. between the primary and 

 secondary coils at the minimal response. 



Time of 



Muscle in solution of strychnine. 



Nerve in solution of strychnine. 



immersion. 



Muscle in 



Nerve out 



Muscle j out 



Nerve in 



3 min. 



6 min. 



9 min. 

 12 min. 

 15 min. 

 30 min. 

 57 min. 

 72 min. 



9 cm. 

 9 cm. 

 9 cm. 

 8 cm. 

 7 cm. 

 6 cm. 



5 cm. 



6 cm. 



37 cm. 

 37 cm. 

 35 cm. 

 24 cm. 



no response, 

 no response, 

 no response, 

 no response. 



18cm. 

 18cm. 



16 cm. 



14cm. 



17 cm. 

 14cm. 

 13cm. 



9 cm. 



10 cm. 



9 cm. 



8 cm. 



9 cm. 

 9 cm. 



10c,m. 

 12 cm. 



* In recent practical classes, strychnine replaced curare in the repetition 

 of Claude Bernard's experiment on muscle-irritability. 



