cumscribed sclerotitis about the insertion of the external rectus muscle of the right eye. There had been no mechanical injury to the eye. Patient was experiencing no other difficulty save a severe aching of the second molar tooth on the same side. There was profuse lachrymation of the right eye. Treatment produced no perceptible good until the carious tooth was extracted, when the inflammation subsided as if by magic.

ON THE CAUSE OF THE DIASTOLE OF THE VENTRICLES OF THE HEART.

BY A. H. GARROD,
St. John's College, Cambridge.

The existence of an active diastolé of the ventricles of the heart following each systolé has been long recognized by physiologists, and there have been several explanations given of the phenomenon; but they are all subject to grave objections, and fresh methods of research have overthrown them one after another.

The object of the present article is to show that this active diastolé is mainly dependent on the turgescence of the walls of the heart, consequent on the flow of blood into the coronary arteries immediately after the systolé.

The experiments of Vaust in 1821, together with the known anatomical arrangement of the commencement of the aorta, strongly favor the supposition that during the ventricular systolé the circulation in the walls of the heart ceases on account of the close relation between the segments of the aortic valve and the orifices of the coronary arteries.

Immediately the aortic valve is closed the impediment to the flow of blood into the coronary vessels is removed, and the sudden repletion thus caused, directly after the closure of the valve, produces an equally sudden turgescence of the walls of the ventricles, the auricles from their thinness not being similarly affected. This turgescence of the tissue of the heart produces an active opening out of the cavities of the ventricles, and in a very short time they reach their maximum

size.

The following experiment supports this theory: Take a sheep's heart which has at least two inches of the aorta left on; attach the cut end of the aorta to a pint syringe full of water and inject; the first effect of this operation is the closure of the aortic valve, immediately after which water enters the coronary arteries, the ventricular walls swell and the cavities of the ventricles open out to their full extent. It will be then found that the heart is tough and not easily compressible, and if it be cut in two between the apex and the base, the halves

shew the cavities fully dilated, and they remain so until the water has escaped from the cut orifices of the vessels. The shortness of the coronary arteries and the sudden way in which they break up into minute ramifications favors the rapid turgescence of the heart walls.

If this theory be correct it follows that there must be an absorptive force exercised in both the ventricles immediately after the closure of the aortic valve, and Marey found that to be the case when he placed in either ventricle an ampoule registering negative pressures only.

The relation between the cardiograph traces from the ventricles and aorta throw so much light on the point under consideration that a detailed description of them will not be out of place.

The diagram is taken from Marey's work De la Circulation du Sung, p. 189.

NI

NII

น

No. I. is the trace from the left ventricle.

No. II. is from the aorta.

Simultaneous events are recorded in the same longitudinal lines, and the traces by their rise and fall indicate alterations of pressure in the ventricle and aorta respectively.

No more reference will be here made to the systolic than is necessary to explain the diastolic movements.

Towards the end of the cardiac systolé, the pressure which continues to increase in the ventricles (v) diminishes in the aorta (b), because then the latter receives less blood from the heart than it transmits to the capillaries.

After this; it is considered by Marey that the undulation x in the upper trace corresponds with c in the lower, and that they are both caused by the closure of the aortic valve; he also thinks the fall between x and z in the upper trace to be due to the relaxation of the ventricle, and, without explaining why, states that at that moment the pressure falls ordinarily below zero. But on carefully looking at his own diagram, as copied above, it is clearly seen that the undulation

с

in the aortic slightly precedes in the ventricular trace, and this together with the results obtained by Chauveau, by means of his combined haemadromometer and sphygmoscope, and confirmed by Lortet. leads me to doubt the correctness of Marey's explanation and to advance the following:

During the main ventricular descent the aortic pressure increases (c), probably from the rise of the base of the heart after its contraction, just as at the commencement of the systolé it falls (a) from the opposite cause.

When all contraction has ceased, the only impediment to regurgitation from the arteries, is the passive resistance of the ventricular walls, which is comparatively slight; so that blood flows back to the heart, compressing the ampoule into the ventricle and causing the elevation x in the upper trace, while it necessarily produces a similar depression in the lower one.

When the reflux of blood has become sufficiently rapid, the aortie valve closes, and in so doing puts an abrupt stop to the ventricular rise x. Immediately after this the coronary repletion and consequent turgescence commences, as shewn above, and by opening out the cavities of the entricles, diminishes the pressure on the contained ampoule. and so depresses the trace below zero.

This tendency to the formation of a vacuum, together with the associated raising of the base of the heart, causes so great a rush of blood from the auricles, which as Mr. Bryant has shown, are then quite full, that a slight undulation is produced in the ventricular

trace z.

The increase in bulk of the ventricular walls, consequent on the coronary repletion, takes place in all directions, and by expanding the whole conical heart, pushes the base up into the cavity previously occupied by the full auricles, which it simultaneously empties by the absorptive force.

This theory being true, the heart is a machine in which simplicity of action and economy of force are most marked. The systolic movements fill the reservoirs which are to feed the cavities they empty : and all the diastolic forces are expended in active preparation for the succeeding systolé; the circulation in its walls besides its primary object, even aiding its mechanical function.—Journal of Anatomy and Physiology, May, 1869.

TREATMENT OF SUNSTROKE..

(This is the concluding portion of a lecture on Sunstroke, delivered by Dr. G. M. Smith, at the New York Hospital, and found in the Medical Record, July 15th:)

I come now to speak of the treatment of sunstroke. In speaking of the therapeutics I must recall the ordinary varieties of the disorder. The milder form, or that of ordinary syncope, is to be treated,

as has been before stated, like cases of faintness; the graver form of syncope, or that of sudden and profound collapse, requires the immediate exhibition of restoratives. The nervous system has been overwhelmed, and vital action has almost ceased. The means suited to relieve such a condition are obvious.

We will consider the treatment of a more typical case. What indications are there to guide in its management? Under ordinary circumstances man maintains a temperature of about 98° F. If the weather is extremely cold, and if, by reason of improper food, raiment, or shelter, he is unable to generate and maintain the proper amount of heat, his body becomes cooled, and a fall in temperature of a few degrees makes him lethargic. When in this condition he is readily frozen to death.

Now what occasionally happens in our midst during the intensely hot weather? The same vital action is generating in man a uniform warmth. Unsuitable aliment, and clothing, conjoined with exposure to an unusually heated atmosphere and to other unfavorable conditions, favor an undue accumulation of heat in the body. The individual falls insensible, the thermometer generally indicating that his temperature is above the normal standard.

en

In pyrexial disorders, when the temperature is high, we deavor to lessen its intensity by bathing the forehead and by the internal administration of water and refrigerating draughts. Such means are grateful to and are desired by invalids.

Patients in the condition before indicated are, as we have said, overheated, and it seems rational to attempt to reduce their temperature. They are insensible and can not swallow cooling drinks, and we should therefore apply cold to the head, or, what is better, to the arms, and further even to the neck and chest, and thus expose a larger surface in which the blood can be tempered.

If the case is an extreme one, and the temperature is very high, it may be well to strip off all the clothing and sponge the entire body with cold water, or to use the sudden cold douche; and if these means are insufficient to cool the patient and to rouse him, it may be necessary to apply ice to the head and axillæ, and to rub the trunk and extremities with the same material.

The use of ice in such cases was introduced into this hospital in 1857, by Dr. B. Darrach, at that time Resident Physician. In the American Journal of the Medical Sciences for January, 1859, he published a report of four cases treated in this manner; three recovered and one died. In the fifty-three cases to which I have alluded ice to the entire body has scarcely been employed. It has frequently been applied to the head, but for general cooling it is doubtless safer to rely upon sponging and the douche.

It should constantly be borne in mind that cold is a most powerful remedy. These patients have a tendency to collapse, and if intense cold is unnecessarily employed, it may hasten such an unfortunate condition.

Be careful, therefore, to suit the degree of the cooling process to

the gravity and condition of the patient, and carefully watching the effect of treatment, cease the applications at the earliest practicable moment. Resort is not to be had to the ice frictions until is is found that cool sponging or the douche have failed to reduce the temperature and to revive to partial consciousness.

Some patients come into our hands while in a state of collapse, being cadaverous in color and temperature. It would obviously be improper to employ such treatment in these cases; they have passed the stage in which refrigerant means are indicated, and now require artificial heat, sinapims, warm frictions, and stimulating enemata to restore them.

In many cases in which the cooling process is applied, we find that the temperature of the body has diminished, the respirations become more natural, the pulse less frequent, and that consciousness has returned. This favorable condition may occur in a few moments or may not be reached for several hours, during which time, however, the harsher method of treatment is not to be continually applied, but the gentler partial applications.

In some instances the temperature falls, but there is imperfect consciousness and delirium-such patients are to be carefully dried, placed comfortably in bed, and stimulating enemata exhibited, while the head can be kept cool if extraordinarily heated. As the lungs are generally early congested, it is desirable to place sinapisms on the extremities and chest, or upon the latter dry cups may be employed. By thus favoring the peripheric circulation we lessen the liabilities to pulmonary and to other centric engorgements.

Dr. Beatson, surgeon in the India service, has encountered sunstroke among the troops under his charge, and gives the following concise directious in reference to the immediate treatment: "Unfasten as quickly as possible the man's dress and accoutrements, to expose the neck and chest, get him under the shade of a bush, raise his head a little, and commence the affusion of cold water from a sheepskin bag, continuing the affusion at intervals over the head, chest, and epigastrium, until consciousness and the power of swallowing return. When this takes place the affusion may be stopped and a stimulant mixture given occasionally in small doses.'

In regard to the use of stimulants, I would remark that the same caution must be taken in prescribing them as in ordering cold applications. As soon as the patient can swallow, water can be allowed. If the pulse is frequent and feeble, stimulants are to be given, regulating the quantity by the effect produced. I have already spoken of the condition of the circulation in the malady under consideration. In administering the alcoholic and diffusive restoratives, be governed by the force and frequency of the pulse. Their inconsiderate exhibition. will prove as injurious as their judicious employment will prove salu

tary.

To illustrate the promptness with which patients can be restored, it may be stated that eleven of the cases, to which allusion has before been made as having been admitted here in an unconscious condition