Such being the external phenomena of the breathing of asthmatics, what are the auscultatory sounds that accompany it? They are exactly such as we should expect -exactly such as are consistent with these external phenomena, and such as imply, if the spasm is severe, an almost impassable bar to the ingress and egress of air. On applying the ear to the chest we hear-respiratory murmur none; and this is not because it is drowned by other sounds; if no other sounds are present it is equally inaudible; it is because the conditions of its production do not exist, because sufficient air is not admitted to generate it; just as there is no respiratory murmur in the longdrawn inspiration of hooping-cough, or beneath thoracic parietes fixed by pleurisy or intercostal rheumatism. And this suppression of the ordinary breathing sound is a proof of the depressed standard at which respiration is being carried on, and of the completeness with which air is locked out of and into the chest. The sounds that are heard are dry tube-sounds, large and small-rhonchus and sibilus of every variety, of every note and pitch, and in all parts of the chest, converting it into a very orchestra; but the sounds are mostly sibilant, high and shrill, resembling the chirping of a bird, the squeaking of a mouse, or the mewing of a kitten. And this smallness of sound makes me think that it is almost exclusively the smaller tubes that are the seat of the constriction, whilst the diffusion of the sounds all over the chest shows that constricted tubes exist everywhere.

There is one other fact, in relation to the sounds of asthma, that I think is instructive, and that seems to me to imply that the points of stricture are constantly changing their place, that spasm is constantly disappearing in one part and making its appearance in another, and that fact is, that the sounds are continually changing their character and site. On listening over a part of the chest where a few minutes before you heard a loud shrill sibilus you find it gone, while a part that just before was silent is the seat of a chorus of piping. Now, if the sounds were of a moist character, if they were caused by mucus, I grant that such an inference could not be drawn, for sounds so caused may be, and constantly are, suddenly removed by cough, or other dislodgment of the accumulated secretion; but in the early part of an attack of uncomplicated spasmodic asthma there is no accumulation of mucus in the air tubes-they are dry; the narrowing of the tube, therefore, that gives rise to the musical sound, being solely dependent on bronchial spasm, solely admits of removal by the relaxation of that spasm; and the frequent cessation and change of place of the pipings shows that the spasm that causes them is transient and wandering.

The auscultation, then, of the asthmatic shows us these things:

a. The almost perfect stagnation of air in the chest, in spite of the violent respiratory efforts.

B. That the tubes are generally very small.

7. That tubes in all parts of the chest are simultaneously affected.

6. That the points of constriction are constantly changing place.

ART. IV.

On the Effects of Rupture of the Internal and Middle Coats of Arteries. By GEORGE SCOTT, M.D., Southampton, formerly one of the Physicians to the British Hospital at Renkioi, Dardanelles.

THE following causes of arterial obstruction are usually enumerated:-viz., 1. Acute inflammation of the artery or arteritis. 2. Rupture of the internal and middle coats. 3. Degenerations of the arterial coats, such as ossification, calcification, &c., of such a degree as to cause great rigidity of the vascular walls, and great diminution in the calibre of the artery. 4. Coagula or pieces of valves, &c., becoming loosened from the

5.

central organ of the circulation-the heart, or from the internal surface of some of the larger arteries, and conveyed to, and impacted in, a more distant arterial canal. Coagula which have formed in the veins, have become loosened thence, been carried into the right cavities of the heart, and ultimately propelled into some of the branches of the pulmonary artery.

As regards the first cause usually assigned for arterial obstruction, it seems to me that the experiments made by Professor Virchow in 1847, and detailed in his 'Collected Memoirs,' at p. 395,* satisfactorily prove that simple acute inflammation of the arterial walls is not alone sufficient to cause coagulation of the blood in the vessel at the inflamed part; and the experiments described below also show that inflammation of the arterial walls of such a degree as to cause great thickening of the latter, is unattended with coagulation of blood in, and consequent obstruction of, the vessel.

The proper subject of this paper, however, is with the second of the causes above mentioned-viz., with the effects of the rupture of the internal and middle coats of an artery.

As is well known, when a ligature is tied tightly round an artery, the external coat or adventitia, from its superior elasticity, resists the pressure of the ligature, while the middle and internal coats are divided. On this occurring, it has been stated by many writers that the divided coats coil or curl up on themselves to such a degree as partially to occlude the vessel. That, however, this coiling or curling up of the ruptured internal coats does not often occur, any one may be convinced of who chooses to make the following experiment. Tie an artery of a dead human body, or of a dead animal, with a twine ligature sufficiently tightly to rupture the internal and middle coats of the vessel, then open the latter. The rupture of the inner coats will be indicated by a clean line or furrow, but no appearance of coiling or curling up of the divided coats will be seen. On the contrary, the whole extent of the intima and media remains quite adherent to the adventitia, except at the ruptured part.

If, again, the internal and middle coats be ruptured, as they well may be, by pulling strongly at both ends of an artery removed from the body; on cutting open the vessel, the intima and media will be seen to be divided in many places, but there is no curling or coiling up of the same; the edges of the ruptured membranes are seen to be perfectly on a level with the uninjured portions of the intima.

The experiments detailed below show, that when the internal and middle coats of arteries in the living body of animals are divided by a ligature tied round the vessel, there is scarcely ever any coiling up or inversion of the edges of the divided coats, but the results are in a great measure similar to what occurs in the dead body.

I am not aware of the existence of any disease of the arteries which effects such an alteration in the texture of their walls as to cause the internal and middle coats to curl up when divided, any more than they do in a healthy condition.

It is this idea of the curling up or inversion of the inner coats of arteries when divided all round the vessel, which has, I imagine, more than anything else, contributed to give rise to the supposition that arterial obstruction may be caused simply by rupture of the internal and middle coats of the vessel. Many cases of arterial obstruction are recorded in medical literature which have been attributed to rupture of the inner coats of the vessels. Before, however, referring to them, I shall first give an account of some experiments made by myself upon dogs, with the view of ascertaining the effects of rupture of the internal and middle coats of the arteries during the lifetime of the animals.

Last year, in the Pathological Institute of the Charité Hospital, Berlin, I instituted the following experiments:

EXPERIMENT I.

January 12th, 1858.-A large, smooth-haired mongrel dog, which had been some weeks previously much weakened by loss of blood after division of the optic nerve, was

* Gesammelte Abhandlungun zur wissenschaftlichen Medicin, pp. 895-400.

operated upon in the following manner. The left femoral artery was exposed to the extent of about three quarters of an inch, proceeding downwards from just below Poupart's ligament. A silk ligature was now passed round the vessel, and tied tightly in a single knot, loosened again immediately and removed, and the wound sewed up. The right femoral artery was afterwards tied in the same way, the ligature removed, and the wound sewed up. On removing the dog from the table, and placing him on his legs, he fell down, not able to stand. The weakness seemed to be chiefly in his hind legs. January 13th, noon.-Pulsation can be felt below the points in both femoral arteries, where they had been tied by the ligatures, but the pulse in both is weak and thready. January 15th.-The dog was killed to-day. First, the jugular vein was opened, and he lost about one pound of blood. Not dying then, he was dispatched by wounding the spinal cord in the neck.

Autopsy. The wound over the right femoral artery was gaping, the edges being separate to the extent of at least an inch. The artery for about half an inch above and below the point where it had been tied by the ligature, was adherent pretty firmly to the surrounding tissue. On opening it, the intima and media were seen to be divided completely all round the vessel, but no coagulum of blood whatever was found in it, either at the point of division of the internal coats, or in any part from its origin to nearly its termination in the toes. The wound over the left femoral was nearly healed, otherwise the appearances were exactly the same on this side as on the right, the inner coats being seen to be divided all round the artery, and no coagulum whatever being found in the vessel.

EXPERIMENT II.

January 18th, 1858.-A small white mongrel-terrier bitch was operated upon in the following way. The right carotid artery was exposed to the extent of about half an inch, the same tied tightly in a single knot with a silk ligature, the latter loosened and removed immediately, and the wound sewed up.

January 20th.-The left femoral artery of the same dog was exposed to the extent of about three quarters of an inch, tied tightly with a silk ligature in a single knot, the latter loosened again and removed immediately, and the wound sewed up. The pulsations of the artery below the wound could now be distinctly felt on placing the finger over it. The dog was afterwards placed on his legs. Its left hind leg seemed to be somewhat stiff, but otherwise it ran about as usual.

January 22nd.-The right femoral artery was treated in the same way as the left was two days ago. On application of the finger below the point tied, the vessel could be distinctly felt beating immediately after the wound was sewed up.

January 23rd.-Killed the dog to-day, by opening the left carotid artery, and then by wounding the spinal cord in the neck.

Autopsy. The wound over the right carotid was covered with a large scab, and the edges were found to be separate under this. The artery just in the neighbourhood of the point where it had been tied was not very much more adherent to the surrounding parts than it should have been. There was a reddish line to be seen on the outside around the artery where it had been tied five days before. On opening the vessel no coagula were found in it, but only a very little thin, liquid blood at the point tied; the intima and media were seen to be perfectly divided, and the two ends of the same were about one-eighth of an inch apart, the lower edge of the divided internal coats being turned downwards and protruding into the cavity of the vessel. The artery was traced and opened as far as possible towards the head, but nowhere was a vestige of a clot of any kind to be found. The inside of the artery, where it was deprived of its inner coats, and the edges of the divided coats, were of a reddish colour. The wound over the left femoral was gaping, the edges were hard and thickened, and there was some sanious-looking fluid in the cavity of the same. The artery was adherent pretty firmly to the surrounding parts at the point, and in the neighbourhood of, where it had been tied. A red line was also seen on the outside of this vessel, showing the point where the ligature had been. On opening the artery, the inner coats were seen to be com

pletely divided, but the cut edges were only about half a line apart from each other; there was no inversion of the same, neither was there in any part of the vessel, from the aorta to below the knee, any trace of clot. There was only a little thin fluid blood. The wound over the right femoral artery was closed, but its edges were easily separated by traction. This artery also had a reddish line on the outside, showing where the ligature had been; but the vessel was not at all abnormally adherent to the surrounding parts at the point, and in the neighbourhood of, where it had been tied. On opening the vessel it presented much the same appearance as the left femoral. No coagula of any kind were to be seen in it, so far as I examined.

EXPERIMENT III.

February 3rd. The animal operated on was a small, white, long-haired mongrelterrier bitch. The left femoral artery was exposed to the extent of about half an inch, and then tied tightly with a silk ligature in a single knot. The ligature was removed almost immediately after its application, and the artery was then felt beating again strongly below the point where it had been tied. The wound was now sewed up, and the dog let go; she seemed to run about as well after this as before the operation.

February 11th.-Tied the right femoral artery with a silk thread a short distance below Poupart's ligament, as in the former case, and loosened the ligature again immediately. Directly the ligature was loosened the artery could be felt beating strongly below the point where it had been tied. The wound was sewed up again immediately after the removal of the ligature, and the dog let loose. She ran about afterwards as well as she had done before the operation.

February 20th, half-past one P.M.-After having etherized the dog, I exposed the right common carotid artery to-day to the extent of about two-thirds of an inch, on a level with the cricoid cartilage, and a little above and below this, tied the artery with a silk thread in a double knot, put a suture in the upper part of the wound to bring the edges partially together, and then let the dog go.

February 22nd.-At half-past one P.M. to-day, just forty-eight hours after having tied the right carotid artery, I put the dog again under the influence of either, opened the wound, and with some difficulty removed the ligature from the carotid; then sewed up the wound entirely.

March 4th.-The dog is very much emaciated since the last operation. The wounds over both femorals are completely healed, and the wound over the right carotid is also healed, but covered with a scab. At half-past two P.M. to-day, she was allowed to inhale chloroform until she died, which happened in about a minute after she began the inhalation.

Autopsy. The left femoral artery was removed from the dog immediately after death, but was preserved for some hours in alcohol before being opened; when it was cut open, one or two long coagula of a bright red colour were found lying quite loose in the interior of the vessel; these had evidently been formed after death. At the point where the artery had been tied there was a line showing the rupture of the intima and media; the former was everywhere smooth and normal-looking, except that it presented this rupture; the latter was just at a point where the artery gave off a branch. The right femoral artery was opened immediately after the dog died, and the point where the ligature had been applied was indicated by a line showing where the inner coats were divided. All the rest of the intima looked perfectly smooth and healthy; no coagula were found in the vessel; under the microscope, the cleft between the intima and media was seen to be nearly filled up with connective tissue. The right carotid artery was very adherent to the surrounding parts at the point, and a little upwards and downwards from the point, where it had been tied. The knot of the ligature had been removed, but a portion of the thread had remained on the artery at the back part, but merely on the wall of the vessel, and not apparently diminishing the calibre of the same; the coats of the artery were very much thickened at the point tied. On opening the vessel the inner coats were seen to be completely divided, and

the ruptured ends about half a line separated from one another. There were merely one or two long bright red coagula, not adherent to the walls of the artery, but lying quite loose in its interior. I conclude, therefore, that these clots must have been formed after death, as the artery was several hours in alcohol before being opened. At all the other parts of the vessel the intima looked perfectly smooth and healthy.

EXPERIMENT IV.

15th February.-A long-haired poodle, about eighteen inches high, was operated upon in the following manner: I exposed, at one P.M. to-day, about half an inch of the left femoral artery just below Poupart's ligament. Then tied the same tightly with a silk thread. I could feel the pulsation distinctly just above the point tied, but below this no pulsation was to be felt after the ligature was applied. I left the wound as it was until five P.M. of the same day, when I removed the ligature and sewed up the wound. It should be mentioned, that after the ligature was applied and the dog let loose, he walked about as well as before the femoral artery was tied.

18th February.-At eight A.M. to-day I exposed the right femoral artery just below Poupart's ligament, to the extent of about half an inch. Tied the artery with a silk thread in a double knot; then left the wound open and let the dog loose. He seemed to walk about as well as before the ligature of the femoral-Five P.M. Cut away the ligature from the artery, and closed the wound with one suture.

26th February.-At two P.M. to-day I exposed the right carotid artery to the extent of about one-third of an inch, and then tied it with a silk ligature in a double knot. Closed the lower part of the wound with two sutures, and then let the dog go.

27th February.-At half-past two P.M. to-day, put the dog under the influence of ether, removed the ligature from the right carotid artery, and sewed up the wound. 5th March.--Killed the dog to-day with chloroform.

Autopsy. The wounds over both femoral arteries were completely healed; that over the right carotid was still open and suppurating. The left femoral artery, when opened, was seen to be pervious in all its extent; there were only one or two soft coagula lying quite loose in its interior. At the point of the artery which had been tied, the inner coats were seer to be divided all round the vessel. Under the microscope the division of the intima and media was very distinctly seen, but a portion of the cleft was filled up with connective tissue, which had formed, of course, subsequently to the application of the ligature. There was no inversion or coiling up of the inner coats of the artery at the point where these were divided. The right femoral artery was unusually adherent to the neighbouring parts at the point where it had been tied, and a little above and below this. On opening the vessel the cavity was seen to be perfectly free and pervious, and at the point which had been tied the intima and media were seen to be completely divided all round the vessel. There was, however, no inversion of the edges of the ruptured tunics. Under the microscope about the same appearances were seen as in the left femoral artery. The right carotid artery, at the point tied and a little above and below this, was very adherent to the neighbouring parts. On opening the vessel, the intima and media were seen to be completely divided all round the artery, and the divided edges were about a line apart. The cavity of the vessel was perfectly free and pervious, and no coagula were found in it. The intima everywhere else but at the point divided, was perfectly smooth and healthy-looking. Under the microscope the cleft between the divided intima and media was very distinctly seen.

By the preceding experiments we perceive that when the inner coats of an artery of a healthy living animal are ruptured all round the vessel by means of a ligature tied tightly around the latter and then removed, either immediately or at intervals of four, nine, twenty-four, and forty-eight hours after its application, the cut edges of the intima and media do not, as has hitherto been supposed, in all cases curl or coil up into the tube of the artery, but for the most part they remain quite smooth and adherent to the adventitia, except at the ruptured point. In only one case in all the preceding experiments-viz., in the right carotid artery of the second experiment-was the lower cut edge of the inner and middle coats slightly inverted, and projecting into the tube.