64 MEMOIRS NATIONAL ACADEMY OF SCIENCES, VOL. X, NO. 3. 



In Experiment 28, with the large heart of a good-sized snapping turtle, one-half of 1 per 

 cent of alcohol raised the heart work from 177 to 213, a gain of 20 per cent. 



In addition to the experiments, the details of which have been given, we have made others 

 with the hearts of large frogs, in which the results reached were entirely concordant with those 

 just tabulated. It should be noted that in many of these experiments the alcohol was repeatedly 

 used and withdrawn and used again, and that each time the heart work rose and fell with the 

 giving and withdrawing of the alcohol, and that in no experiments with the large heart did the 

 alcohol fail clearly and positively to manifest its influence. 



The results of all the experiments which we have made clearly establish that when the 

 isolated reptilian heart is placed under conditions as nearly natural as is possible, the amount of 

 blood which it will pump during a fixed period — i. e., the amount of work which it will do — is 

 increased usually from 10 to 15 per cent by the addition of one-quarter to one-half per cent of 

 alcohol to the nutrient fluid. In these experiments it was usually apparent that the increased 

 work was manifested by the increase in the amount of blood thrown out by the heart at one 

 systole, and it appeared to us that the alcohol increases the completeness of the diastole. 



RELATION TO PREVIOUS INVESTIGATION. 



The facts which we believe we have experimentally determined in regard to the action of 

 alcohol upon the circulation are: 



First. In the normal dog alcohol does not usually, either in small or large dose, distinctly 

 increase the arterial pressure, although occasionally such an effect appears. 



Second. The action of alcohol upon the circulation in dogs suffering from an infective fever, 

 at least so far as the blood pressure is concerned, is similar to its influence upon the normal dog. 



Third. After section of the spinal cord in the cervical region, with artificial maintenance of 

 the respiration, alcohol distinctly and consistently increases the arterial pressure; in other words, 

 alcohol increases arterial pressure after the general vascular system has been separated from 

 its dominant vaso motor centers. 



Fourth. (Series 5.) The exhibition of small doses of alcohol increases very markedly the 

 rate of flow of blood through the large arteries, as measured by Ludwig's stromuhr; this increase 

 of rate being consistently maintained under the repetition of the intravenous injection of alcohol 

 until the time comes when the rate of flow gradually lessens under the paralytic influence of the 

 toxic dose of alcohol upon the heart and blood vessel. The increase of the rate of flow is in 

 no wise dependent upon nor related to any elevation of the arterial pressure, as it may occur 

 without the pressure being sensibly affected. 



Fifth. (Series (!.) One-quarter to one-half per cent of alcohol added to the nutritive fluid 

 feeding an isolated working reptilian heart markedly and persistently increases the amount of 

 the fluid pumped in a given length of time by the heart; that is, markedly increases the work 

 done by the heart. If one-half to 1 per cent of alcohol lie added to the nutritive fluid there may 

 be a primary condition of increase of work, followed in a few minutes by marked lessening of 

 the work clone. Larger percentages of alcohol immediately decrease the activity of the isolated 

 reptilian heart. 



The first question which naturally arises at this point is as to how far the above facts which 

 we seem to have established agree with the results obtained by previous experimentators; let us 

 look at this matter in a consecutive manner. 



First. Without more elaborate discussion we think that anyone conversant with the litera- 

 ture of the action of alcohol upon the blood pressure will acknowledge that the general drift of 

 the evidence is in accord with the results which we have reached. Most observers affirm they 

 have been unable to get any increase of the arterial pressure by the use of alcohol, whilst others 

 allege that they have obtained such increase. Attempts have been made by critics to reconcile 

 these differences by asserting the incompetence of one set of observers, the critic attributing 

 these qualities to one or the other set of observers according to his own opinion on the subject. 

 It seems to us much more probable that both sets of observers have recorded correctly their 



