46 



Dr. F. B. Nunneley on the Physiological [June 17, 



XXII. " The Physiological Action of Atropine, Digitaline, and Aconi- 

 tine on the Heart and Blood-vessels of the Frog." By Frederic 

 B. Nuxneley, M.D. Lond. Communicated by Dr. Bast I an. 

 Received June 16, 1869. 



(Abstract.) 



These experiments were undertaken with the view of determining more 

 exactly the physiological action of atropine, digitaline, and aconitine on the 

 heart and blood-vessels, by methods of experiment which have hitherto 

 been little followed out. 



My experiments on atropine have led me to the conclusion that it exerts 

 no action on the blood-vessels, a result which differs from that of Mr. 

 Wharton Jones and of M. Meuriot. This opinion was adopted after a 

 lengthened examination of the natural circulation in the frog's web, and 

 of the numerous spontaneous changes which it undergoes, and also of those 

 which are the result of the slightest irritation. It is some of these changes 

 which have, I think, been assigned by the observers just named to the 

 special action of atropine. 



Different opinions have been entertained with regard to the action of 

 digitaline on the heart ; the result of my observations is given below. Aco- 

 nitine has also a very marked action on the heart, the opposite of that of 

 digitaline ; its physiological effects are stated. 



In actually conducting the experiments, the general symptoms of a 

 poisonous dose were first observed, so as to show the period at which the 

 heart lost its vitality in relation to the rest of the body. 



Next, the visible effect produced on the heart, exposed in situ, was noted 

 as regards the quality, frequency and rhythm of its contractions ; and also 

 the alteration seen to occur in a heart removed from the body and immer- 

 sed in a solution of the alkaloid. 



Lastly, the effect on the blood-vessels of the web, was examined with 

 the aid of the microscope. 



The results obtained have been thrown into the form of conclusions. 



Atropine, digitaline, and aconitine do not produce any effect on the ves- 

 sels of, or circulation in, the frog's web, whether locally applied in the 

 form of solution, or injected under the skin at a distant part, so as to in- 

 fluence the animal generally ; in the latter case, as they tend to impair or 

 abolish the functions of the heart, the circulation necessarily undergoes 

 secondary changes ; but these alterations do not occur until the heart is 

 visibly affected. 



Atropine. — 1. A few minutes after a dose of about ^ 0 gr., the frog be- 

 comes quiet, sinks down on the plate containing it and makes ineffectual 

 efforts to jump, the respiratory movements cease and it dies in from 1^ to 

 3 hours. On exposing the heart, it is found beating, and the contractions 

 continue for some hours. 



2. The action of atropine on the heart is neither considerable nor ener- 



