114 



DR RUTHERFORD ON THE INFLUENCE OF THE VAGUS 



I might give the results of nine other experiments similar to the foregoing, 

 but these so thoroughly agree with the above that I think it unnecessary to 

 detail them. I shall, however, have occasion to refer to some of their results in 

 the sequel. 



EXPERIMENTS ON FROGS. 



EXPERIMENT XIII. — Strong Frog. Both Vagi Divided. Larynx laid open anteriorly. 

 Heart Exposed. Pericardium Unopened. 1 Daniell. 







Pulse in Half a Minute. 





Time. 



Distance in Millimetres of 



Primary from Secondary 



Coil. 





State of Laryngeal 



Muscles. 



Before Irritation of 



During Irritation of 







Vagus. 



Vagus . 











Eight vagus. 





9-ir 



800 



16 



16 



Rest. 



•14' 



800—750 



16 



16, 16 



>i 



•17' 



750—700 



16 



16 



J! 



•19' 



700—650 



16 



16 



>3 



•22' 



650—600 



16 



16 



J) 



•26' 



600—550 



16 



19 



Contraction. 



•30' 



560 



16 



16, 16 



Rest. 



•34' 



550 



16 



15, 16 



Contraction. 



•37' 



550—500 



16, 16 



16,16 





•43' 



500—450 



16 



16, 16 



j» 



•48' 



450—400 



16 



16, 16 



>■> 



•53' 



400—350 



15 



15, 15 



>9 



•56' 



350—300 



15 



16, 15 



>i 



•59' 



300—250 



15 



15, 15 



)) 



10-4' 



250—200 



14 



14, 13 



» 



•9' 



200 



14 



14, 12, 12 



» 



•14' 



200—170 



14 



12, 12, 10 



>> 



•20' 



170—140 



15, 14 



14, 12, 11 



» 



■25' 



140—100 



15 



8, Arrest. 



>> 



The left vagus was then irritated, but only with a view to ascertain what was 

 the feeblest current necessary to produce movement in the larynx, and also the 

 weakest current which could arrest the heart's movements. A current at 530 

 mm. was the weakest which threw the left recurrent laryngeal nerve fibres 

 into action, while the weakest which sufficed to arrest the heart was one at 

 170 mm. Further observations on the left vagus were not undertaken, seeing 

 that the heart's action had become irregular. 



