EXCITABILITY OF THE VAGUS ROOTS. 



511 



The left vagus remained intact. A -3^ solution of the watery 

 extract was used. 



Time. 



m. s. 







1 01 



2 20/ 



3 30 



4 

 4, 30 



6 



€ 



7 



8 



9 

 9 30 



10 0\ 

 10 5J 



10 8 



15 0\ 

 15 30/ 



Condition before experiment . . 



The normaliBxcitability of the 

 central end of the right 

 vagus was then tested ; it was 

 found that coil 10° produced 

 slight slowing of the pulse 

 and fall of blood-pressure, 

 while the respirations became 

 slower and deeper. This was 

 the slightest irritation which 

 produced any effect . . 



Condition after irritation 

 •5 c.c. injected 



Condition after injection 



Kise of blood-pressure. iNo 

 alteration of pulse. Eespira- 

 tions quickened and respira- 

 tory oscillations increased 



Central end of right vagus irri- 

 tated. Coil 15° 



No effect 



Central end of right vagus irri- 

 tated. Coil 10° 



Same effect as before injection. 



Second injection of 1^ c.c. 



Clot formed and removed 



Condition before irritation 



Irritation with coil 10° 



The thorax remained in a state 

 of pennanent inspiration 

 during irritation, while the 

 effect on the heart and blood - 

 pressure was nil 



Irritation with coil 6* . . 



No effect on heart. Respiration 

 as before 



Condition immediately follow- 

 ing irritation . . 



Slowing of pulse. G-reat fall 

 of blood-pressure. Great 

 oscillation. Systole and dia- 

 stole of same length, with no 

 pause between them 



Irritation with coil 8° . . 



As before there was no effect on 

 the blood- pressure or pulse, 

 and there was permanent in- 



Pulse 



in 

 10 sec. 



38 



30 

 34 



34 



34 

 38 



43 



40 



40 



12 



40 



