interesting to notice the theory advanced and supported by our author. Perhaps the most generally received opinion is that the brain is in a state of approaching congestion. Drs. Carpenter, Dickson, and Sir Henry Holland, as well as others, assert that "a degree of pressure is essential to perfect and uniform sleep." Dr. Hammond, however, objects very strongly to this theory, and attempts to prove by experiments, that natural sleep proceeds from a cause, the exactly opposite of that held by the well known names mentioned above.

"That stupor may be produced by pressure upon the brain admits of no doubt. It is familiarly known to physicians, surgeons, and physiologists; the two former meet with instances due to pathological causes every day, and the latter bring it on at will in their laboratories. But this form of coma and sleep are by no means identical. On the contrary, the only point of resemblance betweeen the two consiststs in the fact that both are accompanied by a loss of volition. It is true, we may often arrive at a correct idea of a physiological process from determining the causes and phenomena of its pathological variations, but such a course is always liable to lead to great errors, and should be conducted with every possible precaution. In the matter under consideration it is especially of doubtful propriety, for the reason stated, that coma is not to be regarded as a modification of sleep, but as a distinct morbid condition. Sir T. C. Morgan, in alluding to the fact that sleep has been ascribed to a congested state of the brain, for the reason that in apoplectic stupor the blood-vessels of that organ are abnormally distended, objects to the theory, on the ground that it assimilates a dangerous malady to a natural and beneficial process. He states (what was true at the time he wrote) that the condition of the circulation through the brain, during sleep, is wholly unknown.

"It is important to understand clearly the difference between stupor and sleep, and it is very certain that the distinction is not always made by physicians; yet the causes of the two conditions have almost nothing in common, and the phenomena of each are even more distinct.

"1. In the first place, stupor never occurs in the healthy individual, while sleep is a necessity of life.

"2. It is easy to awaken a person from sleep, while it is often impossible to arouse him from stupor.

"3. In sleep the mind is active, in stupor it is as it were dead."

"4. Pressure upon the brain, intense congestion of its vessels, the circulation of poisoned blood through its substance cause stupor, but do not induce sleep. For the production of the latter condition a diminished supply of blood to the brain, as will be fully shown hereafter, is neces

sary.

"Perhaps no one agent so distinctly points out the difference between sleep and stupor as opium and its several preparations. A small dose of this medicine acting as a stimulant increases the activity of the cerebral circulation, and excites a corresponding increase in the rapidity and brilliancy of our thoughts. A larger dose lessens the amount of blood in the brain, and induces sleep. A very large dose sometimes diminishes the power of the whole nervous system, lessens the activity of the respiratory function, and hence allows blood which has not been properly subjected to the influence of the oxygen of the atmosphere to circulate through the vessels of the brain. There is nothing in the opium itself which produces excitement, sleep, or stupor, by any direct action upon the brain. All its effects are due to its influence on the heart and blood-vessels, through the medium, however, of the nervous system."

Dr. Hammond performed experiments to prove the above. He took three dogs and placed them under the influence of chloroform, and from each removed a portion of the upper surface of the skull an inch square. The dura mater was also removed. Three hours after when the effect of the anesthetic had passed away, he gave one dog, one-fourth of a grain of opium, the next dog one grain, and the third dog, two grains, the brain of each being in a natural condition :

"At first the circulation of the blood in the brain was rendered more active, and the respiration became more hurried. The blood-vessels, as seen through the openings in the skulls, were fuller and redder than before the opium was given, and the brain of each animal rose through the hole in the cranium. Very soon, however, the uniformity which prevailed in these respects was destroyed. In number one the vessels remained moderately distended and florid for almost an hour, and then the brain slowly regained its ordinary appearance. In number two the active congestion passed off in less than half an hour, and was succeeded by a condition of very decided shrinking, the surface of the brain having fallen below the surface of the skull, and become pale, As these changes supervened, the animal gradually sank into a sound sleep, from which it could easily be awakened. In number three the surface of the brain became dark, almost black, from the circulation of blood containing a superabundance of carbon, and owing to diminished action of the heart and vessels it sank below the level of the opening, showing, therefore, a diminished amount of blood in its tissue. At the same time the number of respirations per minute fell from 26 to 14, and they were much weaker than before. A condition of complete stupor was also induced from which the animal could not be aroused. It persisted for two hours.

During its continuance, sensation of all kind was abolished, and the power of motion was altogether lost.

"It might be supposed that the conditions present in numbers two and three differed only in degree. That this was not the case is shown by the following experiment:

"Experiment.-To the dogs two and three I administered on the following day, as before, one and two grains of opium respectively. As soon as the effects began to be manifested upon the condition of the brain, I opened the trachea of each, and, inserting the nozzle of a bellows, began the process of artificial respiration. In both dogs the congestion of the blood-vessels of the brain disappeared. The brain became collapsed, and the animals fell into a sound sleep, from which they were easily awakened. If the action of the bellows was stopped, and the animals were left to their own respiratory efforts, no change ensued in number two, but in number three the surface of the brain became dark, and stupor resulted. In order to be perfectly assured upon the subject, I proceeded as follows with another dog:

"Experiment. The animal was trephined as was the others, and five grains of opium given. At the same time the trachea was opened, and the process of artificial respiration instituted. The brain became slightly congested, then collapsed, and sleep ensued. The sleep was sound, but the animal was easily awakened by tickling its ear. After I had continued the process for an hour and a quarter, I removed the nozzle of the bellows, and allowed the animal to breathe for itself. Immediately the vessels of the brain were filled with black blood, and the surface of the brain assumed a very dark appearance. The dog could no longer be aroused, and died one hour and a quarter after the process was stopped."

Our author then enunciates his theory which, in a modified form, has been brought forward before by Blumenbach-but not received with much favour. He says: "I believe that sleep is directly caused by the circulation of a less quantity of blood through the cerebral tissues than traverses them while awake." He then states an experiment made by Dr. Fleeming of Queen's College, Cork, who tried the effect of compressing the carotids on the functions of the brain-the result being a gradual insensibility which continued so long as the compression was kept up. The interesting volume by Durham on the Physiology of Sleep is alluded to. Dr. Hammond stating that previous to its publication he was engaged experimenting in the same direction-but yields to Mr. Durham the priority, and states that his experiments were not carried as far as those of Mr. Durham's.

"In 1854 a man came under my observation who had, through a

frightful railroad accident, lost about eighteen square inches of his skull. There was thus a fissure of his cranium three inches wide and six inches long. The lost portion consisted of a great part of the left parietal, and part of the frontal, occipital, and right parietal bones. The man, who was employed as a wood chopper, was subject to severe and frequent epileptic fits, during which I often attended him. In the course of my observations, I soon became acquainted with the fact that, at the beginning of the comatose condition which succeeded the fits, there was invariably an elevation of that portion of the scalp covering the deficiency in the cranium. As the stupor passed away, and sleep from which he could easily be aroused ensued, the scalp gradually became depressed. When the man was awake, the region of scalp in question was always nearly on a level with the upper surface of the cranial bones. I also noticed on several occasions that during natural sleep the fissure was deeper, and that in the instant of awaking, the scalp covering it rose to a much higher level.

"After my attention was thus drawn to this subject, I observed that in young infants the portion of scalp covering the anterior fontanelle was always depressed during sleep, and elevated during wakefulness."

Various other experiments were performed on dogs-portions of the skull being removed, and ether and chloroform being administered. With the ether the brain sank below the inner surface of the skull, and the vessels which could be perceived contained dark blood-as the anesthetic passed off the circulation of the brain became more active, and its volume increased. With chloroform the effect was differentthere was no sinking of the brain substance-on the contrary, it protruded. "Not only was unoxygenated blood circulating to a great extent through the brain, but there was very decided congestion." As another illustration, Dr. Hammond alludes to the soporific effect heat has, and ascribes it to the amount of blood which flows during high temperature to the surface of the body, consequently diminishing the amount going to the brain. Excessive loss of blood also produces sleep, says Dr. H., which is easily accounted for by the theory he advances as the immediate cause of sleep-but which is difficult he says to explain upon any other hypothesis.

In many ways the theory advanced by Dr. Hammond is a very plausable one—and while we must admit that he has brought forward much to support his theory, we still feel that his experiments are not all quite satisfactory to our own mind. However much credit is due him for the able manner in which he has handled his subject—and eventually much good will result from its publication.

We have devoted so much space to the first portion of the volume, that but little is left us in which to notice the latter part. Wakefulness is a complaint which every physician is constantly brought face to face and often the treatment adopted-in the majority of cases, opium or its kindred preparations, gives but little benefit. We generally find this complaint in persons, whose brains have been overtaxed by mental exertion. Mental effort long continued, demands an active brain circulation-hence the cerebral vessels have been overdistended, and Dr. Hammond, asserts this over-distention causes the vessels to lose in a great measure their contractile power, hence a larger amount of blood is circulating in an overtaxed brain than was normal. To such patients he recommends a total cessation from active mental exertion-sleep to be sought for, not in the recumbent posture, but in an easy chair in an upright position, stimulants in the shape of whiskey, coffee, &c., and above all the bromide of potassium in doses of ten to thirty grains. From experiments our author states that this salt invariably lessens the quantity of blood circulating within the cranium. We wish that it were possible for this little work to find its way into the hands of every one of our subscribers. Besides helping to pass a couple of hours pleasantly and profitably, (for it is a very interesting volume,) it contains so much of practical value concerning cases constantly coming under observation, which have often been treated unsatisfactorily, that we believe the practitioner would certainly profit much by its perusal.

PERISCOPIC DEPARTMENT.

Surgery.

ON AMPUTATION AT THE HIP-JOINT.

BY JOHN H. PACKARD, M. D., one of the Surgeons to the Episcopal Hospital,

Philadelphia.

The remarks which I have to offer to the readers of the Journal are

based upon a case which occurred at the U. S. A. Hospital at Beverly, N. J., last winter. By the courtesy of Dr. Clinton Wagner, U. S. A., the surgeon in charge, under whose orders I was acting as Consulting Surgeon to the Hospital, the manual procedure was entrusted to me; but, as Dr. W. justly remarks in his (unpublished) Report of Surgical Opera. tions, the successful result was mainly due to the surgical skill and the kind and unremitting attention of Dr. J. C. Morton, Executive Officer of the Hospital.