296 



PROFESSOR C. R. MARSHALL ON 



is suggested by the curves, and is supported by the fact that division of the vagi 

 annuls the action of tutin on the circulation but not on the respiration. Systematic 

 observations of the respiration and pulse have not been made after the administration 

 of large doses mainly owing to the fear of exciting convulsions by taking the pulse ; 

 but from the occasional notes made, it would seem that the increase in the frequency of 

 the respiration and the diminution in the rate of the heart-beats are not proportionately, 

 and may not be actually, as great after large as after relatively small doses. 



Heart Resp. 



120 



110 



100 



90 



80 



70 



60 













































































300 





























































































i 









































































1 



\ 



i 









































































i 



\ 











































































\ 





























































i 



> 













\ 







,1* 













































,< 



1 

























1 





/ 

























































\ 















\ 





/ 



\ 























































\ 















\ 



i 

 I 





\ 



























< 



1' 





































l 





\ 



I 





\ 



L 















































250 

















1 





\ 



i 







\ 





















































\ 











1 













V 

 \ 























































\ 









1 













\ 























































\ 









1 















[ 











































































\ 



\ 











/ 



1 









































< 



' 

 i 







► 

















\ 







J 



' 













































\ 





I 



















\ 







/ 















































\ 





1 



















\ 





/ 



I 

















































\ 



1 





















\ , 



/ 



















































\ 



/ 



















/ 



A 







































200 















\ 











/ 



s 



•* 



/ 



/ 







~~ 



— * 



^^ 















































\ 











/ 





s 



/ 

















■^ 



^ 

 ^ 







































/ 



, ! 



> — 



\ 







1 





























~--l 



> 































/ 



/ 







\ 



\ 



1 

























































. i 



| 



— t 



/ 



i — 











\ 



I 



























































\ 



/ 

































































































































































































































































































Minutes. 



20 



40 



60 



80 



100 



120 



140 



160 



Fig. 1. — Diagram showing effect of 0"3 mg. tutin per kg. body-weight on the frequency of the respiration and the heart in a 

 rabbit (weight, 750 grm.). Continued line = number of heart-beats per minute. Broken line — number of respirations 

 per minute. 



During deep anaesthesia the reciprocal relationship between the frequency of the 

 respirations and the heart-beats after tutin is lost. In this condition the administration 

 of tutin usually diminishes the number of respirations per minute, while the circulation 

 remains unaffected or is affected to a relatively slight degree. With chloroform as the 

 anaesthetic, slowing of the respiration after the injection of tutin was invariable. When 

 ether was employed, increased rapidity of the respiration followed if the anaesthesia was 

 light, and slowing if the anaesthesia was deep. The following protocol shows the effect of 

 tutin on the blood pressure, pulse rate, and respiration during chloroform anaesthesia : — 



