Inflammation of the diaphragm. Little reliance can be placed on the accounts given of this affection by ancient authors. There is little doubt that it does occur now and then, in consequence both of wounds of the organ and of internal disease. In the latter case, however, it either originates or else merges in inflammation of neighbouring parts, so that its individual features are not sufficiently marked to offer a distinct portrait. Diaphragmatic pleurisy has no other features to distinguish it from ordinary pleurisy, besides the locality of the pain and its violence during cough, the extreme dyspnoea, and, finally, the occasional accompaniment of singultus. Andral, however, mentions also the presence of nausea and vomiting, even in certain cases in which the stomach was found quite healthy. Sometimes a very distressing hiccup attends convalescence, -or adhesions take place between the lung and diaphragm, giving rise to permanent shortness of breath. When the right side is affected, the liver often becomes implicated, as is then manifested by icteric symptoms, &c. and the disease is often mistaken for hepatitis. Diaphragmatic is more perilous than costal pleurisy, on account of the greater embarrassment to the respiratory function. The treatment is that of ordinary pleurisy. The singultus attending some cases during convalescence, is said to have been successfully combated with the tincture of stramonium.

It is scarcely likely that the peritoneal investment of the diaphragm is ever generally and independently inflamed. This coating is not a continuous one, but is interrupted by folds, thrown off to several of the abdominal viscera, so that its extensive inflammation must needs involve that of one or more of the said viscera. Singultus, dyspnoea, phrenic pain, are common symptoms of the inflammation of organs subjacent to the diaphragm; if, therefore, we even admit the occasional occurrence of simple peritoneal diaphragmatitis, we are familiar with no symptoms distinctive of it. The disease is not unfrequently reflected from the pleura to the corresponding portion of the diaphragmatic peritoneum, which is then found, after death, to have undergone thickening and adhesions; the latter sometimes inclosing tuberculous deposits. In almost all these instances, the intervening muscular fibres appear perfectly healthy. Is not the singultus, before stated to occur now and then during convalescence from diaphragmatic pleurisy, probably dependent upon this implication of the peritoneal coat?

Malformations of the diaphragm. We shall confine our notice to such as would seem at all instrumental in engendering disease. Narrowness of the foramina deserves to be mentioned in the first place; that of the aortic foramen, recognized by Haller, may occasionally have some share in the production of thoracic aneurism. Of narrowness of the other foramina no authentic cases have been recorded; at the foramen quadrilaterum it is not very likely to occur, owing to the strong tendinous fibres by which that passage is protected. There are better grounds for believing dysphagia to be now and then a consequence of this malformation at the foramen œsophageum.

A more important vice of organization (where it can be deemed such) is that denominated diaphragmatic hernia, and which consists in the formation of a diverticulum or hernial sac, the short end of which is directed upwards, within the thorax, whilst the base opens into the abdomen. This sac is, for the most part, diminutive, but occasionally exceedingly

capacious, and it always contains a smaller or greater proportion of abdominal viscera. The parietes of the sac sometimes consist of the serous investments of the diaphragm only, -the muscular fibres having merely undergone separation; at other times the walls include the muscular fibres, and the hernia is simply a partial distension of the organ along with its serous coats. In the majority of cases these herniæ have been accidentally discovered during the dissection of bodies, without any symptoms having even denoted their existence. In a few of the recorded instances, however, the enormous mass of abdominal organs, both hollow and parenchymatous, contained in the sac, cannot have failed to produce the greatest disturbance to the organs, both of circulation and of respiration. There are examples of a violent blow struck against the abdomen, sufficing to produce fatal hernia at the anterior portion of the diaphragm, situate between the sternal and costal portions, where no muscular fibres occur, and the two serous sacs therefore meet. Hernia occurring in the body of the diaphragm is probably, in most instances, dependent on congenital malformation.

Ectopia, or the displacement of abdominal organs through an opening in the diaphragm is discussed by Dr. Mehliss at considerable length, with a view to discriminate between the cases dependent on arrest of primary development and those resulting from accident or disease. Total absence of the diaphragm is only met with in the instance of acephalus. Four marked cases are cited of infants who did not long survive, and in whom the greater portion of the left half of the diaphragm was found wanting. In each the left thoracic cavity was found encumbered with an enormous mass of abdominal viscera. In the adult the inference is in favour of congenital malformation: 1st. Where the opening is very wide, and the edges of the wound smooth and even, presenting no marks of cicatrization. An acquired rent of the same extent must needs have proved speedily fatal. 2d. Where there is actual want of substance. Mere rupture could not occasion this. 3d. Where the opening occurs in the tendinous portion, where the fibres are least of all likely to give way.

The passage of pus and other fluids, or of acephalocysts through the diaphragm, is generally followed by collapse and cicatrization, or else by adhesions between the muscle and some contiguous organ, so that no permanent opening becomes established. It has been before stated, that an important symptom of extensive displacement of the bowel, consists in a notable sinking in of the abdomen. This is not, however, invariably perceptible; for it is remarkable that Nature appears bent upon compensating for the dislodged viscera, by causing the dilatation or enlargement of those that still remain. The liver, in particular, is then sometimes found to have attained a prodigious size. Of the descent of thoracic organs into the abdominal cavity, through an opening in the diaphragm, we have no well-authenticated record. Such an opening did not appear to exist in Vetter's interesting case of a vigorous man's heart being situate in the left hypochondrium, where it could be grasped with the hand, and its contractions and dilatations distinctly felt.

The question of how the opening originated is chiefly interesting in a medico-legal point of view; since the lesion itself, however produced, is obviously beyond the reach of art. Still the mere suspicion of its ex

istence, (for certainty there cannot be)-offers sufficient grounds for the immediate employment of those precautionary measures into which the treatment of this grave affection must resolve itself. Of gastrotomy, for the purpose of replacing the extruded viscera, though seriously suggested by Laennec,-there can surely be no further question at this time of day.

Adhesions of the diaphragm with neighbouring organs are frequently met with as a consequence both of superficial and latent inflammation, and of other destructive diseases. They of course seriously interfere with the functions of the diaphragm, more especially when occurring with the subjacent organs. Nothing, however, with certainty denotes their existence during life. Dr. Mehliss infers from a case observed by himself, that the circulation may become seriously embarrassed by these adhesions involving the foramina through which the great blood-vessels traverse the diaphragm.

Parasitic formations in or upon the diaphragm. The various kinds of eruption stated to have been found on the diaphragm, are all referable to an earlier period of pathology. We must restrain the temptation we feel to give our readers the benefit of a full-length portrait, drawn with medieval circumstance by Lanzoni, of a lascivious female, (salacissima quædam muliercula), who, being alarmed during the act of parturition (?) fell into a convulsive state, with alternate fits of hiccup and of laughter, which, after forty hours' duration, terminated in death. The diaphragm was found "undequaque vesiculis polyporum colore protuberans, quarum nonnullis phlebotomia adopertis, emanabat serosus liquor, colore aqueo, sed acidissimo odore imbutus." Dr. Mehliss regards this as a case of vesicular eruption,-Joseph Frank, with more verisimilitude, as one of hydatids. A remarkable case of hydatid cyst is recorded by Pohl, (Diss. Lipsiæ, 1747). It was twenty-six inches long and fifteen wide, and situate at the inferior surface of the diaphragm, which it had forced far into the thorax. A longitudinal incision gave escape to some 200 acephalocysts, of various sizes, from that of a fist downwards. The narrator believed the principal cyst to have formed through distension of the cellular tissue situate between the muscular fibres and the peritoneum. The subject was a female, aged 26, and far advanced in her third pregnancy. The trichinia spiralis has occasionally been met with in the muscular substance of the diaphragm.

But we have already somewhat surpassed our proper limits, and must needs conclude. Those amongst our readers who are familiar with the German language, will do well to procure Dr. Mehliss's work, which, upon the whole, cannot but be regarded as a valuable contribution to pathological literature.

ART. XII.

1. Erste Gründe einer Physiologie der eigentlichen thierischen Natur thier ̄ ischer Körper: entworfen von Dr. JOHANN AUGUST UNZER.-Leipzig, 1771.

Principles of a Physiology of the Animal Nature, peculiar to Animal Bodies. By Dr. J. A. UNZER.-Leipsic, 1771. Svo, pp. 734.

2. JOHANN AUGUST UNZER'S Physiologische Untersuchungen. Auf Veranlassung der Göttingischen, Frankfurter, Leipziger und Hallischer Recensionem seiner Physiologie, &c.-Leipzig, 1773.

UNZER'S Physiological Inquiries: in reference to the different Reviews of his Work on the Physiology of the Animal Nature.-Leipsic, 1773. 12mo, pp. 149.

THE Principles of a Physiology of the Animal Nature peculiar to Animal Bodies, propounded by Unzer, is a work on Vital Dynamics generally, but specially on the Dynamics of the Nervous System.

In our original prospectus, issued twelve years since, we announced our intention of giving retrospective reviews: our readers, therefore, ought not to be altogether unprepared for the present article. But in truth it was not to fulfil our original intentions that we undertook the examination of Unzer's book, but rather that having our attention called to the volume during our investigation of the doctrines of Prochaska, we were struck by the lucid views and close reasoning of the author; and indeed, as to some points, by the novelty of the opinions propounded. We learnt too, that while anatomy had advanced so largely, vital dynamics had made little progress; or if it might be allowed that in some points of doctrine the science had advanced, in others it had really retrograded. In short, we felt that on the whole the movement onwards of the philosophy of life was сит exili et quasi contemnendo progressu," ," and that good service would be done to science by reproducing doctrines like those of Unzer, and giving them that wider scope of application which an improved anatomy admits of, and which, indeed, the loud claims to a newer and truer philosophy of certain modern neurologists imperatively demands. Nor is the review of such a work less interesting and amusing than it is instructive. We witness a powerful mind extending its palpi into paths which we now traverse freely, and trying to penetrate a gloom which to us is effulgent light. We anxiously watch his approach to some truth now familiar to us; and then see his steps turned away just when about to seize it and emerge from the surrounding darkness. But we see, too, that if he have turned away from truths lying at his feet, he has overlooked them because he has been engaged in straining his eyes towards the far horizon; and that it was the wide extent of his view which led him to overlook the near and the obvious;-the grandeur of his conceptions, which wiled him from the full enunciation of those principles on which others have since hoped to establish an exclusive reputation.

In introducing the subject of his book to the reader, Unzer sets out by placing an imaginary corpse before himself. Regarding this attentively, he sees nothing there but matter subject to the ordinary forces of matter. There are solids with the property of cohesion; fluids subject to the laws of hydrostatics. The arteries are tubes contracting on the finger in virtue

of their physical elasticity, and receiving the injections of the anatomist simply according to the laws of hydraulics. The heart beats not; the contracted muscles maintain the limbs in a motionless position; the machinery of the body is still.

In the living organism matters are far otherwise. It is true the elementary forces of matter act on its components, but other forces are seen in operation upon them, acting according to other laws, and in a definite order. The stimulus which excites no motion in the lifeless heart, in the dead muscle, or in the devitalized arteries, maintains the circulation in the living body, alters the pulse, and excites contractions of the muscles and movements of the limbs. These forces which the living animal possesses, in addition to those of the dead, are "the proper animal forces or powers,' (die eigentlichen thierischen Kräfte,) and give it that nature which the author terms "the proper animal nature of animal bodies," (die eigentliche thierische Natur thierischen Körper.)

The reader will better understand the analysis of Unzer's doctrines if he will form a distinct and definite conception of what the author means by the word Kraft. This word corresponds to the Latin vis, and to the English words force and power. The force of gravity is the power of attraction inherent in matter; the centrifugal force is the power of repulsion. The two words are continually used as synonymous, but they are not strictly synonymous. Force is power in the abstract; power is force in action, according to law and arrangement. The elastic force of vapour is the power of the steam-engine. The term power has been used also to express the property or quality of a body; as, for example, the " conducting power" of various substances has been ascertained by experiments in thermotics and electricity; how incorrectly, if the two words, force and power, be synonymous, is made manifest by simply substituting the word force for power, for we have then the conducting force of iron as regards caloric, the conducting force of water as regards the magnetic imponderable. That Unzer means to use the word Krüfte to signify primary powers or forces of living matter, just as we speak of the force of gravity, the power of attraction, &c., is manifest from the context and the sentiments of the whole work:

"The ordinary science of physiology considers the forces or powers (Kräfte) of animal bodies in their natural condition and as they act together in connexion with each other, but without distinguishing the simply physical and mechanical from the proper animal forces or powers (Kräfte). This presupposes that we know the laws according to which each of these separate forces or powers (Kräfte) operate separately, and indeed as to the physical and mechanical, whose laws are known, there is generally in reality no difficulty. The physiological works of Haller teach us, in a manner almost impossible to be surpassed, the mechanism of all parts of the animal body, of which the structure develops the functions according to the laws of mechanics, hydrostatics, hydraulics, optics, acoustics, &c. But do we know those laws by which the proper animal forces or powers (Kräfte) govern the body when acting separately from the physical and mechanical, and independently of them? Truly no! or at least very imperfectly. The thoughts and desires or emotions of the soul or mind [Gedanken und Begierden der Seele] are animal moving forces or powers (Kräfte) of the animal body. But do we at this moment know anything of the laws by which these forces regulate their appropriate mechanism (Maschinen)? or have we hitherto troubled ourselves to observe the operation of these laws in each particular class of ideas and desires? We have disputed stoutly enough, whether the soul be matter or brain; whether