4. Inflammation of the arterial walls, of such a degree as to cause great thickening of the same, and consequently a considerable diminution in the calibre of the vessel, is insufficient of itself to cause coagulation of the blood in, and consequent obstruction of, the artery at the point inflamed.

I may also venture to observe that it remains yet to be proved that there exists any disease of the arterial coats producing such an alteration in the texture and physical properties of the inner tunics as to cause the same, when ruptured, to curl up into the tube, and, by mechanically occluding the canal, induce coagulation of the blood at the injured part.

The objection to these conclusions may be made, that there are many well-authenticated cases recorded in medical literature of arterial obstruction caused by rupture of the inner and middle coats of the vessel. Of the fact that obstruction of the arteries did occur, of course there can be no doubt, but the alleged cause of the obstruction must, in my opinion, be called in question. In all such cases, save one, that I have been able to find recorded, the obstruction seems to me quite as easily explained on the embolic theory of coagula sent from a distance and becoming impacted in the arterial canal, as on the hypothesis of rupture of the inner coats of the vessel.

Thus Dr. Oke of Southampton, in the Provincial Medical Journal,' vol. iv. p. 51, 1842, relates a very interesting case of arterial obstruction, which he attributes to "spontaneous rupture of the internal coats of the artery, and the projection of its edges into the tube;" and in the third volume of the 'Transactions of the Medico-Chirurgical Society of Edinburgh, 1829,' there is a paper by Mr. Turner on Obstruction of the Canals of the Arteries, describing ten cases, the obstructing cause in all of which is referred to "rupture of the internal coats of the arteries."

For a detailed account of the above cases reference must be made to the original papers, as it would occupy too much space to reproduce them here. Suffice it to say that all the eleven above-mentioned cases, with the exception of the third and fourth, of Mr. Turner, are evidently cases of embolus, where the affected vessels have been suddenly obstructed by coagula or cardiac vegetations conveyed to them from a distance. In cases of the latter kind it must be observed,

1. That it by no means follows that because there are no physical signs of cardiac disease, therefore the case cannot be one of embolus, for coagula may form, as they pretty frequently do, in the left auricular appendage of the heart, pieces of them may afterwards become loosened thence and conveyed into some distant arterial canal; or again, the blood may coagulate in the pouch of a cardiac aneurism, and portions of the coagulum may become separated and propelled into some of the peripheral arteries without their having been necessarily any symptoms of valvular disease of the heart in affected.

the person

2. That more than one artery of the body usually becomes stopped up, and these vessels are generally affected at different times, e.g., the main artery of one arm of, a person may all of a sudden become obstructed, and then in a few days afterwards precisely the same symptoms may seize upon one of the legs, as in Mr. Turner's first

case.

3. The obstruction caused by an embolus generally occurs at the part of an artery where the calibre of the vessel suddenly diminishes-viz., at the point of division into two or more branches.

4. When a piece of blood-coagulum or any other foreign body becomes impacted all of a sudden in an artery, the irritation of the same sets up inflammation of the walls of the vessel, the latter become thickened, adherent to the surrounding parts, and the intima dies and separates from the media. That the death of the intima is in such cases a consequence of the irritation of the foreign body, is shown by the fact of this tunic being usually destroyed only at the obstructed point, and being in the rest of its extent of quite healthy appearance.

Now, in all the above nine cases, which seem to me quite easily explicable on the embolic theory, the symptoms of obstruction came on suddenly; in most of them there were well-marked pectoral symptoms, either before or after the stoppage of the circulation in the affected arteries, thus showing that there was in all probability cardiac

derangement, although perhaps not valvular disease to be detected by the ear during life; in five the obliteration took place in either more than one vessel or in more than one part of the same vessel, and in the two cases where there was a post-mortem examination of the affected vessels, the obstructions were found at points of division of the vessels into smaller branches, and in these two cases, everywhere but at the affected portions of the vessels, the intima was perfectly healthy in appearance, except in Turner's first case, where at one part of the popliteal artery there was a small crucial fissure or laceration of the internal coats, but where, nevertheless, there was no coagulation of the blood in, or consequent obstruction of, the vessel.

The third case mentioned by Mr. Turner appears to me to be one of embolus also, although I must confess that it is by no means so evidently so as the nine before mentioned. As the case is somewhat remarkable, I shall detail it here at length. It was under the care of Dr. Abercrombie, of Edinburgh.

"The patient, a man named John Anderson, aged sixty-three, first complained on 6th November of a fixed pain about the top of the right thigh and groin, and after a day or two the thigh became numbed and weak, gangrene of the whole limb came on, and the man died on the 13th November.

"On examination of the body after death, there was found a great quantity of a darkcoloured fluid effused into the limb, and the muscles were universally dark and gangrenous behind the peritoneum; on the right side of the abdomen there was a large gangrenous cavity, containing much dark-coloured fluid and ill-conditioned pus. The femoral artery being laid open, there was found disease of the inner coats in several places. These were soft and separated at various points from the outer coat, so as to lie across the area of the vessel like valves. One of them was about a third down the thigh, and there were others less remarkable. On slitting open the external iliac artery, the inner coats were found soft and thick, and at one place completely lacerated in the whole circumference of the artery, and separated from the external coat for nearly an inch and a half, the portion thus separated having fallen down and coiled up, so as completely to obstruct the canal of the artery nearly at the place where it passes under Poupart's ligament. Between this and the origin of the internal iliac artery there were consid rable lacerations of the inner coats. In two places they were slightly detached from the outer coat, and their edges projected into the tube of the vessel. Above the obstruction at the lower part of the iliac, produced by the more extensive laceration, there was a coagulum of blood in the artery. The aorta was in several places diseased, its internal surface ulcerated, and the inner coat partially separated. In some of the smaller branches of the arteries in the pelvis there was ossification, but none in the right iliac artery, where this singular disease was situated. The left iliac artery appeared sound. No other diseased appearances were detected. It is obvious that the obstruction to the circulation was produced by the torn and detached internal coats of the artery."

The description of the post-mortem appearances in this casê is certainly very imperfect, so that the following remarks upon them are quite open to correction.

It is said that the inner coats of the femoral artery were in several places soft, and separated at various points from the outer coat, so as to lie across the area of the vessel like valves. There is no mention, however, of any blood-coagula being found in these portions of the affected vessel; now this must surely have been the case if, during life, the internal tunics lay like valves across its cavity; unless coagula had been there some time previously and had softened down, the artery meanwhile becoming obstructed higher up, and so the blood prevented gaining access again to the vessel after the breaking down of the first coagula. Neither is the structure of the blood-coagulum situated above the obstruction at the lower part of the iliac artery described, so as to enable one to form an opinion as to whether its nucleus was constituted by a thrombus or any foreign body conveyed from a distance, or whether the coagulum had formed entirely at the spot itself. Then the aorta was in several places diseased, and its internal surface ulcerated. Now, there is nothing improbable in the supposition that blood-coagula may have formed at the diseased portion of the aorta, pieces of them have subsequently become loosened thence, and been propelled into, and have obstructed, the femoral and iliac arteries in several places and at different periods, the gangrene and separation from the adventitia of the internal coats being a secondary affection caused by the irritation of the emboli. Under such circumstances, the coagula in the most distant

parts of the artery from the centre would, of course, have been the oldest, and would perhaps have had time to soften and break down, while those higher up nearer the centre, being of more recent date, would have been found still entire; which indeed were just the appearances described by Dr. Abercrombie.

In Mr. Turner's fourth case, which came under his own observation, the cause of obstruction of the affected vessel is certainly involved in obscurity. The following is an account of the case:

"A German of middle age, a strong, muscular man, fell down a steep stair when drunk, and sprained his right elbow-joint. On examination, there was found to be a great degree of swelling and tension of the soft parts around. There was no fracture or dislocation to be discovered, but the joint appeared looser than natural, as if some of the ligaments had been torn. Mr. Turner was surprised, on endeavouring to feel his pulse at the wrist, not to be able to discover any pulsation in the radial artery, neither could he detect any in the ulnar nor in any part of the arteries of the fore-arm. The pulsation of the humeral artery was distinct up to the bend of the elbow. Next morning, when sober, he complained of violent pain in the arm. The swelling and tension were rather increased. The absence of pulsation in the arteries continued. He was sent to the Edinburgh Royal Infirmary, and Mr. Turner did not see him for more than a fortnight after this. At that time the swelling and pain of the elbowjoint had almost entirely subsided. On examining the arteries of the fore-arm, no distinct pulsation was to be felt, and pulsation in the humeral artery could be distinctly felt to the fore-part of the elbow joint, where it suddenly ceased. The fore-arm was pale, and the veins much smaller and more collapsed than those in the other arm, and when they were compressed they filled very slowly. Sensation and motion of the fore-arm and hand were perfect. The patient ultimately recovered perfectly."

"Mr. Turner thinks that cessation of the pulse must be here accounted for in the same way as in the cases already related-that is, by rupture of the internal coats of the artery. The artery could not have been torn across, otherwise there must have been an extensive effusion of blood into the cellular substance of the arm and fore-arm, of which there were no symptoms; nor could the pulse have been stopped by pressure from the effusion into, and consequent tension of, the parts surrounding the artery. Usually no such effect is produced, and the stoppage would not have been permanent, but the pulsation would have returned as the swelling and tension abated, as they began to do very soon after the accident."

Even if rupture of the internal coats had been sufficient to cause obstruction in the artery, it is difficult to conceive how such an injury could have occurred in this case. The humeral artery might have been considerably bruised by the fall the man had, but mere bruising of an artery, unless with a sharp instrument like the teeth of a forceps,* is not sufficient to cause rupture of the internal coats, much less obstruction of the vessel. This is shown by my sixth experiment, where the right femoral artery, being raised on a copper spatulum, was bruised by striking it several smart blows with a percussion hammer without causing any rupture of the inner tunics; and also by my seventh experiment, where the left femoral artery of another dog was similarly treated, and with a like result.

The only explanation I can think of is that, previous to the occurrence of the injury to the elbow, there may have been obstruction of the lower end of the humeral artery, which had until then escaped notice.

* See Experiment VII.

PART FOURTH.

Chronicle of Medical Science

HALF-YEARLY REPORT ON PHYSIOLOGY.

BY HERMANN WEBER, M.D.

Licentiate of the Royal College of Physicians, Physician to the German Hospital.

I. DIGESTIVE OR RGANS.

1. BOULEY and TROUSSEAU: On the Effects of the Ligature of the Esophagus in Animals. (Brown-Séquard's Journal of Physiology, vol. i. p. 777. 1858.)

2. BROWN SÉQUARD: Remarks on the Phenomena Consecutive to the Ligature of the Esophagus. (Brown-Séquard's Journal, vol. i. p. 799, 1858.)

3. ECKHARD: On the Influence of the Irritated Sympathetic Nerve on the Secretion of Saliva. (See Sub. IV., Nervous System.)

4. FUNKE: On the Endosmotic Qualities of the Peptons. (See Sub. III.)

IN July, 1856, Bouley stated before the Academy of Medicine, as the result of many experiments, that ligature of the oesophagus is by no means an indifferent operation, as Orfila had maintained, but that it causes very serious symptoms, and even death, and that the inferences drawn from experiments implying ligature of the oesophagus, can be accepted only with great discrimination. In consequence of this statement, the Academy named a commission, consisting of Bégin, Bouley, Jobart, Larrey, Renault, and Trousseau. The report of this commission, as communicated by Trousseau, contains the following inferences:-1. The application of a ligature round the oesophagus is constantly followed by certain symptoms, which require to be taken into consideration in toxicological researches. 2. The symptoms are more or less serious according to the amount of constriction of the oesophagus. 3. Per nanent constriction is fatal in nine-tenths of the cases. 4. Death takes place in the majority of animals between the third and sixth day after the operation. 5. The symptoms characteristic of permanent ligature of the oesophagus are those of extreme prostration. 6. The lesions produced by permanent constriction of the oesophagus, are inflammation of the nerves (accompanying the oesophagus), and of the adjacent parts, either with or without purulent deposits. 7. Temporary ligature of the oesophagus is fatal only in three per cent. 8. As a general rule, the effects are less grave in proportion as the ligature was kept on less long, and the constriction less light. 9. The phenomena produced by ligature of oesophagus can lead to the supposition of poisonous properties in inoffensive substances. 10. The possible effects of ligature of the esophagus ought always to be taken into account in toxicological experiments requiring the ligature of the oesophagus. Brown Séquard remarks that his experiments prove that mere irritation of the nerves of the oesophagus, without obstruction of the passage, cause the same symptoms as those produced by the ligature, though in a less degree; while the ligature round the oesophagus, after the previous section of the oesophageal nerves, is not followed by the phenomena described by Bouley and Trousseau, but only by those of starvation and of inflammation of the wound. Brown-Séquard ascribes some of the principal symptoms of the ligature to reflex action, and promises to prove this view in a future essay on the nutritive phenomena and reflex secretions.

II. BLOOD; CIRCULATION; RESPIRATION.

1. BROWN-SÉQUARD: Experimental Researches on the Physiological Properties of the Red and Dark Blood. (Brown-Séquard's Journal of Physiology, vol. i., p. 729, 1858.)

2. BERNARD: Two Memoirs of the Variations of Colour of the Venous Blood. (Brown-Séquard's Journal, vol. i., p. 649, 1858.)

3. DRAPER: On the Modifications of the Blood-globules in the Spleen. (New York Journal of Med., Sept. 1858; and Brown-Séquard's Journal, vol. i., p. 825, 1858.)

4. GERHARDT: Researches on the Dulness of Percussion from the Heart, and the Change of Place of its Limits in Healthy Persons. (Archiv f. Phys. Heilkunde, Jahrgang, 1858, p. 489.)

5. VIERORDT: Law of Dependence of the Mean Durations of Circulation in various Species of Animals from the Mean Frequency of Pulsation. (Archiv f. Phys. Heilkunde, Jabrgang 1858, p, 527.)

6. FUHRER: On some Outlets (Auswege) of the Circulation of Blood. (Archiv f. Phys. Heilkunde, Jahrgang 1859, p. 145.)

7. BROWN-SÉQUARD: Experimental and Clinical Researches on some Points concerning Asphyxia. (Brown-Séquard's Journal, vol. ii., p. 93, 1859.)

8. VALENTIN: On Respiration after Suppression of Transpiration. (See Sub. III.)

On a former occasion* we have mentioned Brown-Séquard's researches on the physiological properties of the red and of the dark blood. The author has arrived at the following further inferences in connexion with the same subject:-10. In the nervous and contractile organs, the persistence of the possibility of recovering the vital properties after they had completely disappeared, is found to show the following increasing series-brain, spinal marrow, urinary bladder, intestinal canal, uterus, heart, iris, sensitive nerves, motor nerves, muscles of animal life. The limits, hitherto found, were for the brain of an adult dog, twenty-two minutes; for the muscles of animal life of a dog, six hours. 11. To the oxygen contained in the blood, the power of regenerating the vital properties of contractile and nervous tissues must be attributed. 12. The contractile tissues of the principal organs of the animal economy, at all events in vertebrata, can be stimulated by blood saturated with carbonic acid. 13. Blood saturated with carbonic acid also acts as an excitant on nervous tissues.

Bernard has continued his researches on the change of colour of venous blood, derived from various glands, according to the physiological condition of the glands. The experiments which form the basis of the present essay have been performed on the submaxillary gland of dogs. The glandular nerve of this gland appears to come from the fifth pair, but in reality the greater portion of its formed, according to our author, by the chorda tympani. Galvanization of this nerve, through which the function of the gland, and thus profuse secretion of saliva, is excited, causes the venous blood proceeding from the gland to become of a bright red colour, like the arterial blood; at the same time the quantity of blood flowing from the vein appears much increased, and occasionally the motion of the blood is distinctly jerking. A similar result is obtained when the function of the gland is excited by means of substances placed on the tongue of the animal. During the state of rest, i.e., while the gland does not secrete, the venous blood issuing from it is dark. The opposite influence appears to be exercised by the filaments of the great sympathetic nerve, which accompany the glandular branches derived from the external carotid artery. Dissection of these sympathetic filaments is followed by a change from the dark colour of the venous blood into bright red, while the application of galvanism to the peripheric portion of the filaments renders the colour again dark, and diminishes the velocity of the circulation. Corresponding to these changes in colour and velocity, are changes in the diameter of the vessels. The glandular or tympanico-lingual nerve, as Bernard names it, renders the diameter of the capillary vessels larger; the sympathetic nerve, on the contrary, produces contraction. These two kinds of nerves are considered as being in constant antagonisin, their contracting and dilating action is regarded as the cause of all the other phenomena; the physiological action of the nerves producing merely mechanical alteration, which necessarily induces chemical changes. The author dwells especially on the fact illustrated by these discoveries, that each organ or each portion of the body has, to some degree, its own circulation, influenced by modifications in the nervous action, but more or less independent of the general circulation.

In the second memoir, Bernard gives us the result of his chemical examinations, made by means of the oxide of carbon, that the bright red venous blood contains in every 100 volumes 17.26 volumes of oxygen, while the dark venous blood contains only 6:40 volumes, the arterial blood yielding 19:46, i.e. only 2-2 more than the bright red venous blood. Finally, the