300 



Scientific Proceedings (129) 



Epinephrin has been chosen for study because of the readily 

 measurable changes it induces in the diameter of the frog's 

 pupil. The time from injection of the drug to beginning dilata- 

 tion has been designated as the latent period and has been made 

 the basis of comparison of the rates of absorption by the two 

 methods. As the tables and curves (Figures I and II) show the 

 latent period after intramuscular injection is always shorter. 

 It is felt that this rinding further substantiates the above results. 



147 (2107) 



Some effects of morphine upon respiratory reflexes. 

 By M. S. DOOLEY and GEORGE B. ANDREWS. 



[From the College of Medicine of Syracuse University, Syracuse, 



New York.] 



In some unpublished experiments it was found that morphine 

 not only does not diminish the Hering-Breuer reflex, but, on 

 the other hand, actually renders it more prominent, especially the 

 inhibitory phase of it. This appears to be directly opposite to 

 its effect upon other respiratory reflexes such, for instance, as 

 the cough reflex and certain dyspnoeas of reflex origin which are 

 caused to disappear under morphine action. But, for reasons 

 which can not be stated here, we believe that the cough reflex, 

 especially, belongs to a different category and is not to be 

 regarded as a simple reflex and, hence, responds differently. The 

 experiments here reported were devised in an attempt to shed 

 further light on this question. 



It was stated above that especially the inhibitory phase of 

 the Hering-Breuer reflex is exaggerated by the action of morph- 

 ine. This has led us to examine another purely inhibitory res- 

 piratory reflex as to its behavior under the influence of the drug. 

 To do this we have taken advantage of the fact, discovered by 

 Myer, that the active expiration in the fowl is always inhibited by 

 any effective electrical stimulation of the central end of the vagus 

 nerve. For a given strength of stimulus morphine greatly pro- 

 longs this inhibitory reflex rather than diminishing or abolish- 

 ing it. It is thus seen that this reflex reacts toward morphine 

 as does the Hering-Breuer and not as does the cough reflex. 



