1869.] Action of Atropine, Digitaline, and Aconitine. 



47 



getic, a progressive weakening of its power being the most prominent 

 visible effect. The heart continues to beat for some time after the mani- 

 festations of life in the rest of the animal have disappeared ; finally it slowly 

 dies itself, the ventricle being left in a state of relaxation ; this occurs at 

 the end of ten, twelve, or several more hours. 



3. The heart's contraction gradually decreases in frequency and there is 

 no primary acceleration. 



The rhythm of the heart's action is not interfered with ; the auricles 

 continue to beat for some time after the ventricle has ceased to do so. 



4. When the heart is removed from the body and immersed in a solu- 

 tion of sulphate of atropine, it ceases to contract in about the same time 

 that a heart does placed in water ; its appearance does not undergo any 

 change. 



5. The pupil of the frog's eye is not dilated by atropine, either when 

 locally applied or injected under the skin. 



6. The lymphatic hearts cease to contract long before the blood-heart. 

 Diyitaline. — 1. After the injection of about ^ gr. under the skin, the 



frog at first jumps about, then becomes quiet, sinks down on the plate, can- 

 not be easily roused and dies in about from twenty to forty minutes. Some- 

 times the frog has paroxysms of gasping movements, lasting from twenty 

 to fifty seconds, in which it holds its mouth wide open, leaning on its fore 

 paws. These attacks are paroxysmal, whilst the embarrassment of the 

 heart is continuous. On opening the frog, the heart is found motionless 

 and usually unirritable, the ventricle being small and pale. 



Where digitaline if put into the mouth it causes a great secretion of 

 fluid ; in cats the salivation is very marked. 



2. Digitaline acts with great energy on the heart, throwing it into vio- 

 lent and disorderly contractions which quickly end in a cessation of move- 

 ment. The first visible effect occurs a short time after the injection under 

 the skin, and consists in a diminished range of the heart's movements ; 

 but the most marked alteration is a certain embarrassment and loss of 

 smoothness in the heart's contractions, as if there were a want of coordi- 

 nation in the contractions of the individual fibres. 



The ventricular systole presents a peculiar appearance and takes a longer 

 time for its performance than in health ; it appears to travel along, squeez- 

 ing the heart up, as it were, and forcing the blood into one spot, which 

 becomes bright red and projecting ; at the same time there are prominent 

 muscular bundles on the surface of the ventricle giving it an irregular mo- 

 tion. 



During diastole, the ventricle does not everywhere assume a red colour, 

 but one or more irregular red spots appear as if it were so firmly contracted 

 as only to permit the entrance of a small quantity of blood. These spots 

 become smaller and smaller, until at last the ventricle is left very pale, 

 strongly contracted and motionless, whilst the auricles are distended with 

 blood. 



