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its action by introducing through the thoracic wall a finely pointed pair of forceps, and by compressing the vessels at the base by one firm grip; the results will be the same, general muscular tremor, convulsion, spasm, cessation of motion in spasm.

Or we may reduce the temperature of the blood by making the animal breathe an air intensely chilled; the results will be identical in fact, although the time in which such results will be presented may be considerably lengthened.

Lastly, we may modify this line of research by transferring it from the muscular system at large to some particular muscle. We may inject into the structure of such muscle one or other of the agents to which I have referred, or we may reduce the temperature, or we may cut off its blood-supply; and we shall find as results tremor, convulsion, contraction, more or less persistent.

Between the effects produced by all the agents just described and those effects which are excited on muscle by galvanism, there is moreover a great similarity: there are the same contractions and the same pain; and not only so, but symptoms closely analogous to those of cardiac apnæa may be produced by directing a powerful intermittent shock through the chest from the sternum to the lower division of the vertebral column.

The lessons to be gathered from these observations are very important in regard to cardiac apnea. They show that, inasmuch as the arrest of blood to a muscle produces spasm, so cardiac apnea invariably

is excited by any cause that shall rob the heart of the power to feed itself by its coronary vessels, or by any cause that shall so modify the blood as to render it incompetent on entering the coronary system to support the muscle. They show further that the cause of the spasmodic constriction of the chest is the same; that, the heart failing in power, and failing therefore to supply the general muscular system, the involuntary muscles quickly use up their received blood and take on permanent contraction. They explain also why in extreme cases, for the same reasons, the voluntary muscles become similarly implicated.

The question may naturally be asked, why, in all cases of sudden arrest of the heart, the whole voluntary system of muscles is not equally affected with the involuntary during the paroxysm ? The answer to this question is exceedingly simple. In all cases of the kind, the arterial system is left charged with blood, and the muscles therefore are, for a certain time, prepared to withstand the arrest. The involuntary muscles, however, go on acting independently and, consequently, use up their blood-supply, and having used it up assume the contractile state ; but the voluntary muscles, having no necessity for action, undergo less rapid change and remain longer in a state of relaxation, feeding passively, as it were, on the supply of blood which they had previously received. We see this same fact beautifully illustrated in death from hæmorrhage ; as the current of blood is fatally flowing, the heart first ceases, then the muscles of respiration ; lastly the voluntary muscles participate, undergo convulsive movements, and spasmodically contract into inaction.

En résumé, the predisposing cause of cardiac apnea consists always in gradual failure of the mechanical force of the circulation : the exciting cause is anything that shall drive that failure on to suspension of the circulation, and deprive the muscles of blood. Cardiac apnea is virtually, therefore, asphyxia commencing in the circulation.

TREATMENT OF CARDIAC APNEA.

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When once cardiac apnea has proclaimed itself in a definite paroxysm, but little, I fear, can be done to avert a fatal termination during one or other attack. In cases where the paroxysms are slight, or where the warnings only are given, such as have been depicted in the section on “ absolute diagnosis,” we may, nevertheless, if we are convinced that the change which is progressing consists of degenerative tendency in the structure of the heart, advise the patient very greatly to his advantage, and materially reduce the predisposition. Thus, if he be given to habits of intemperance, by far the most fertile source of cardiac muscular atrophy, we may advise him to reformation, may replace his port wine or brandy by a light Burgundy, and entice him to free himself from that external recklessness, irregularity, and exposure, which, not less than the alcohol itself, lay the foundation of disease. I do not, however, for my own part, in these examples, advise sudden and complete removal of alcoholics. I believe that to the habitually intemperate alcohol becomes a form of food; and I know that as a food it cannot be instantly replaced by anything else in the way of sustenance, however wisely the new bill of fare may be selected. For this reason, if ever we do attempt rashly to deprive an alcoholic patient of all alcohol, he immediately begins to lose power ; his sinking sensations, which no simple food can replace, drive him instinctively from our directions to his old resource ; he finds relief in that, and, looking on his Mentor as an impracticable man, returns to alcohol as food, with a more lively appetite for it than ever.

In other cases, where the patient is encumbered with fat, and where it is dreaded that the heart is overburdened externally, or has undergone fatty degeneration, we may render service by recommending such a change in dietary and mode of life as shall tend to reduce the fatty deposit and develope the muscle. In these instances we shall suggest that, as regards food, the patients do reduce the amount of fatty substances, such as butter, or the fat of flesh; next, that they reduce, or remove altogether, substances transformable into fat, especially sugar. I once had under my care a lady, who, encumbered to the last degree with fat deposit, was really in danger. For all articles of diet having a tendency to produce fat, she had a peculiar distaste, except for one, namely sugar; of this she confessed that she would sometimes take half-a-pound, or even a pound a day. I assured her, positively,

that this habit was the cause of her distress, whereupon she had the resolution steadily to give it up; since which time, although she has remained always comely, she has suffered from no serious embarrassment, and has lost all the threatening symptoms of cardiac breathlessness.

Next to reduction of sugar, in these cases, it is well to reduce the amount of beer, and after that of bread; indeed, it is advisable, in most instances, to withdraw the former article altogether, and, if an alcoholic must be taken, to select some of the light French wines, such as claret or Burgundy. In lieu of the fat-forming foods, the patient should be instructed to take the nitrogenous articles of diet in greater quantity, such as eggs, and the lean of meat; while milk, as representing both series of food in perfect proportions, may be used ad libitum. Care should also be taken that the meals be frequent, but each time in small quantity, so that the body may never, on the one hand, become depressed from deficient aliment, nor, on the other hand, overburdened by an excessive supply.

To these regulations in diet, exercise out of doors must always be added : this exercise should never be violent, but, commenced in moderate degree, should be steadily increased until the patient is capable of walking ten or fifteen miles a day without undue fatigue.

Together with these rules, free excretion, renal and alvine, should be maintained; and, occasionally, copious exudation from the skin, by means of the

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