18-i 



IRRITABILITY 



recognized as manifestation of the prolonged refractory period 

 nor as fatigue. A further advance was made by the investigations 

 of Thorner. He placed two nerves of the same frog in a double 

 chamber under completely identical conditions with the excep- 

 tion that one remained in a state of rest, whilst to the other 

 tetanic stimuli were applied. (Figure 35.) If this took place in 



Ji 





-i 



m 



t 



•rJ 



:£!555^^ 



-VWff 



Fig. 35. 



Double glass chamber for comparative experiments on 

 fatigue of the nerve (n n). A and B— Wires of 

 the electrodes. (After Thorner.) 



nitrogen, the irritability of the stimulated nerve invariably sank 

 with much greater velocity than that of the nonstimulated, where- 

 as after an introduction of oxygen, even when the stimulation was 

 continuous, both again recovered. In these experiments of 



