48 



On the Physiological Action of Atropine, §c. [June 17, 



3. The frequency of the heart's contractions is not increased, but is pro- 

 gressively diminished. 



4. The functions of the heart are abolished very early, voluntary power, 

 as shown by the frog's ability to jump about with its heart motionless and 

 contracted, reflex acts and the contractility of the lymphatic hearts sur- 

 viving the death of that organ. 



5. The rhythm of the heart's contractions is but little interfered with 

 unlil near the end, when they become irregular in frequency and force. 



6. Immersion of the heart, removed from the body, in a solution of 

 digitaline causes the ventricle to become somewhat uneven in outline ; the 

 contractions get weak and infrequent and at last cease, sooner by some 

 minutes than in a heart placed in water ; the appearance of the ventricle 

 when it has ceased to beat, presents little that is peculiar, except that it 

 often looks uneven. 



Aconitine. — 1 . After the injection under the skin of about gr. the 

 frog jumps about for a few minutes and then either sinks down on the 

 plate, or else falls over on to its back, as if it had lost both muscular power 

 and the ability to direct its movements ; in either case it dies in from twentj- 

 to forty minutes. If the dose is larger, the frog falls as if stunned, almost 

 immediately after the injection ; from this state it partially revives, but dies 

 at the end of a few minutes. On exposing the heart it is found beating, 

 but rather feebly, and continues to do so for one or two hours. 



2. When the heart is exposed in situ, aconitine is seen to have a very 

 distinct and powerful action upon it. Its contractile power is quickly im- 

 paired giving rise to a peculiar perversion of rhythm. The interval of re- 

 laxation of the ventricle is considerably lengthened, whilst the auricles go 

 on contracting regularly, the consequence is that the ventricle becomes more 

 and more distended with blood, at last a limited part of it contracts, this 

 area of contraction increases with each systole until, in time, the blood is 

 forced, at each contraction, to one part of the heart which projects as a 

 nodule, in a short time the whole ventricle becomes involved in contraction 

 and empties itself in the ordinary way ; soon after the ventricle again enters 

 into a state of relaxation when the same series of acts is repeated. Finally, 

 the ventricle is left large, dark and distended with blood, in a condition 

 exactly contrary to that of a heart arrested by digitaline. 



3. When a heart is removed from the body and immersed in a solution 

 of aconitine it ceases to beat a little sooner than one does placed in water, 

 but presents nothing peculiar in its appearance. 



4. The frequency of the heart's pulsation is increased by a few beats at 

 first, but in a short time there is a progressive diminution. 



5. Although aconitine abolishes the functions of the heart in a compa- 

 ratively short time, voluntary power, reflex acts and the contractility of the 

 lymphatic hearts disappear some time before the blood-heart ceases to beat. 

 The results obtained in about 1 70 experiments formed the basis for these 

 conclusions. 



