blood almost unmixed, and in one instance clotted. Similar effusion also often existed in all the soft parts external to the joint. This effusion always coexisted with vascularity, especially of the fringed folds of the synovial membrane, which were swollen and red. False membranes were occasionally, but not often, found along with the foregoing alterations, and in every instance in which M. Teissier did find them they were already penetrated by vessels, and adhered to the cartilages. The cartilages sometimes presented an uniform or a punctated redness. When the cartilages were not eroded, the redness occurred as ecchymosed macula; when, on the contrary, they were eroded, it was punctated, and in one instance resembled arborescent vascularity, but this, M. Bonnet says, is the result merely of the cartilage imbibing the blood; for though redness by imbibition is uniform when the cartilage retains its natural structure, its surface becomes villous when the imbibition is punctated. Anchylosis is of course a remote result of perfect rest, and, so far as is known, is established by the false membranes adhering, and becoming cellular or fibrous. M. Bonnet gives several cases in which, after fracture of the shaft or of the neck of the femur, the foregoing alterations (excepting anchylosis) were found on dissection, not only in the knee but in the ankle. And M. Velpeau has published two cases which prove the possibility of anchylosis by cellular or fibrous union being caused by long-continued rest. The circumstances that favour the occurrence of those changes in joints when kept motionless are: 1st, the duration of immobility; 2d, old age; 3d, the whole body being kept at rest; 4th, a feeble or cachectic constitution. Whence they are less likely to occur in young, healthy, well-fed persons, and in those fractures, as of the upper extremities, which do not require confinement to bed, or do not take long to consolidate. M. Bonnet thinks it impossible, in the present state of our knowledge, to explain the occurrence of these alterations. From their nature they might be considered inflammatory, and supposed to depend on extension of inflammatory action from a fracture, or on some injury received at the time of the accident; but they occur in the joints most remote from the fracture, and also have been observed where the limb was motionless in consequence of paralysis. Moreover, in cases where the neck of the femur was fractured, the knee and ankle were considerably affected, while the hip was very little so; a result explained by the difficulty of maintaining the hip motionless, while the knee and the ankle are easily kept so. Finally, the alterations arising from immobility are not purely inflammatory; the characters of the sanguineous effusion are analogous to those of scurvy. M. J. Guerin attempts to account for these alterations thus: we have seen that the capacity of a joint varies during motion; in certain motions, therefore, there is a tendency to a vacuum produced in the joint, whence a suction is exerted on its parietes, which excites the exhalation of fluid; and thus he attributes to atmospheric pressure an important influence on the mechanism of serous exhalation. But when a joint is at rest, there is an equilibrium between the external and internal pressure, and therefore no suction and consequent suppression of the synovia; and M. Guerin thinks that the exhalation of the synovia being arrested, the fluids stagnate in the vessels, which leads to congestion and other morbid changes. This explanation, M. Bonnet objects, supposes that the synovia is diminished in quantity; but

the very contrary is the fact. (vol. i, pp. 67-78, and vol. ii, pp. 133-6.) We may here anticipate so far as to say that M. Bonnet deduces from the researches of M. Teissier, from the experiments of M. Guerin on the influence of atmospheric pressure on the exhalation of synovia, and from his own clinical experience, that motion exerts a most powerful influence in modifying the function and morbid condition of a joint; and that a joint should not be kept perfectly motionless for a considerable period in any disease, except in acute inflammations attended with considerable pain, in wounds of joints, and in those chronic cases in which a cure can only be expected from the establishment of anchylosis. (vol. i, p. 132.) But how are we to determine (suppose in a case of acute inflammation becoming chronic,) when immobility is to be replaced by motion? M. Bonnet gives no rule on this point beyond expressing an opinion that, unless some contra-indication exists, rest should not be prolonged beyond six weeks; but he quotes, without expressing any opinion as to its value, the following method for obviating this difficulty, proposed by M. Malgaigne in the Journal de Chirurg. (Oct. 1844):

"A certain method of diagnosis is pressure on the diseased joint, but not on every part of it indifferently, for experience shows that the pain has a place of election in each joint. Thus, in the shoulder, pressure posteriorly sometimes, but rarely, occasions pain; the place of election is anteriorly; elsewhere pressure may be made with impunity. In the elbow the place of election is over the head of the radius; in the hip, at the posterior part of the head of the femur, behind the great trochanter. If the pressure on the head of the humerus, anteriorly and posteriorly, on the anterior and posterior part of the head of the femur, and on the head of the radius, causes no pain, we may pronounce that arthalgia of the shoulder, of the hip, or of the elbow, has terminated, that the period for perfect rest has terminated, and that danger from motion has ceased; and then we should fearlessly encourage the patient to bear with fortitude the pain which he must endure on the very threshold of the second period of the treatment." (Vol. i, pp. 422-3.)

Experiments on mechanical lesions of the joints. Some account of M. Bonnet's experiments on the injuries resulting from forced motions of the limbs may naturally find a place here. It would, however, be superfluous to give a summary of all his experiments,—which, by the way, are detailed at most wearisome length,-both because many of the results are unimportant, and also because they chiefly bear on the history of fracture and dislocations, subjects, except so far as these experiments go, excluded from M. Bonnet's work. We shall, however, in order to give a general idea of M. Bonnet's researches, refer to a few points which may be interesting, either because of their novelty, or their possible practical application.

Fractures of the malleoli of the ankle, and of the inferior extremity of the radius, from violent motion impressed on the foot, or on the hand, are perfectly well known, but it is not so generally understood that analogous motions of the knee, the elbow, the shoulder, and the hip, may also cause fractures of the shafts, or of the articular extremities of the bones.

In the adult, when the leg is rotated violently on the thigh, as a general rule the knee remains intact, and the tibia is fractured about its centre, and the fibula close to its superior articulation; those fractures

are always very oblique, but no relation could be traced between the direction of the obliquity and of the rotation. The tibia is first fractured, and the fibula occasionally escapes, from the motion allowed of in its superior articulation, and from its elasticity permitting of a certain extent of torsion. The fractures of the fibula also may readily escape detection, the fragments being held together by the periosteum, and by the fibrous and aponeurotic expansions which cover the bone at the situation of the fracture. In children the results are usually the same, but in two out of eight experiments, the femur, and not the tibia, was fractured. In one case the femur was twisted just above the condyles, so that the external surface of the shaft corresponded to the anterior surface of the condyles. In the second case there was a very oblique fracture of the lower third of the thigh; the periosteum was only partially torn, and intervened between the fragments when an attempt was made to cross them. We may here mention that he scarcely ever, in his experiments on young subjects, detached the epiphysis the bone was almost constantly broken immediately above the epiphysal cartilages; the deformity was very slight, and the fragments were not completely separated, being in a manner locked by numerous asperities, and always retained by some untorn portion of periosteum; sometimes indeed the periosteum was intact, and had to be divided to expose the fracture.

Generally, as already said, the knee is uninjured when the leg is forcibly rotated on the thigh, but in one experiment the tibia was partially luxated on the femur, and the appearances in this case explain, M. Bonnet thinks, the accident described by Sir A. Cooper and Mr. Key as dislocation of the semilunar cartilage of the knee. In this experiment the foot was suddenly rotated outwards while the leg was bent to a right angle with the femur, and immediately a peculiar sensation of something having slipped (d'un soubresaut particulier) was felt. The foot remained everted and the leg flexed at an angle of about 45 degrees with the thigh; the internal condyle of the tibia projected a little inward and forward beyond the internal condyle of the femur, and the head of the fibula was carried backwards and inwards. On extending the leg gently on the thigh, another slight slip was felt and the bones resumed their natural position; dissection showed that none of the ligaments or of the muscles were torn. M. Bonnet raising the patella to inspect the cavity of the joint again rotated the leg outwards, and saw that the slip or jolt was occasioned by the internal condyle of the femur passing behind the semi-lunar cartilage which was thus thrust forward on the internal articulating surface of the tibia, the capsule of the joint remaining unruptured; the external condyle of the femur was carried very slightly forward but remained in contact with the external semi-lunar cartilage. The joints of the subject experimented on, were, M. Bonnet says, very lax. The appearances in this experiment agree very well with the account of the cases termed dislocations of the semilunar cartilage, as regards the way in which the displacement was occasioned and the mode of remedying it, but differ in the very obvious deformity observed in M. Bonnet's experiment; still we think the experiment throws considerable light on the affection described by Key and Cooper, which, many surgeons suggest, were not examples of displacement of the semi-lunar cartilage but probably cases

of foreign bodies in the knee. M. Bonnet, we have seen, considers that the affection in question, is a partial dislocation of the condyle of the femur, permitted by relaxation of the ligaments of the joint-a view already taken of the affection by Malgaigne; but if the attachments of the semilunar cartilages, both to the tibia and to the capsule of the joint, are very lax, so as to allow them to slide on the tibia, (which is proved by dissection to occur,) then the cartilage may be pushed forwards by the condyle of the femur, instead of the condyle of the femur slipping behind it, as occurred in M. Bonnet's experiment.

To enter into a further account of M. Bonnet's experiments on mechanical lesions of the joints, would lead us too far from the proper subjects treated of in his work; but other occasions will occur on which we can notice them, so far as is necessary, in connexion with fractures and dislocations, to which, as has been already mentioned, they principally refer; and as it would be impossible to examine those parts of M. Bonnet's work which relate to the etiology, symptoms, and treatment of diseases of the joints within the limits now at our command, we shall conclude for the present, and resume the subject in our next Number.

ART. IX.

Untersuchungen über Entstehung des Krankheitsgenius, &c. &c. Von Dr. MARTIN GEIGEL, &c. Würtzburg, 1840.

Researches into the Origin of the Morbid State, &c. By Dr. M. GEIgel, Physician at Würtzburg. 8vo, pp. 480.

THE systematic collection of facts, the task undertaken by Dr. Geigel, is little less advantageous to science than the discovery of them, especially to medical science, in which the relations of a new fact are almost infinitely numerous. The discovery of some general principle in physiology leads necessarily to a completely new arrangement of the whole cycle of medical studies, just as in war a successful movement is followed by a complete change in the position of the corps d'armée. It is fortunate that labourers are never wanting thus to rearrange details, and group the tried experience of the past around the novelties of the present. The development of the modern solido-humoral pathology is the result of a rearrangement like that here alluded to. The humoral pathology based in a great measure upon experience gave way, in consequence of a natural reaction, to that founded upon general and pathological anatomy. The latter branches of medical science having in their turn been cultivated as far as possible by the simpler means of research, the microscope and a more refined chemical analysis were pressed into the service of the inquirer. A new impulse was thus given to physiology and pathology, and two new lines of research marked out, namely, microscopic anatomy and pathological chemistry, the bearings of which upon medical theory and practice are now beginning to show themselves distinctly, and to point to a fusion of what was valuable in the two theoretical systems mentioned.

The factors of the opposite organic conditions, says Dr. Geigel, are the nervous system and the blood. They have a reciprocal action, and consequently neither an exclusively solid nor exclusively humoral pathology can exhibit the

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results of such action. If we would estimatethe morbid action of the nervous system on the blood, we must seek out the material changes in the latter; but we cannot forget on the other hand that the morbid condition of the blood may be the primary cause of these changes. Dr. Geigel's plan includes the consideration of this mutual action and reaction of the blood and nervous system. He first considers the functions of the ganglionic system commencing with an analogy between them, as seen in the fetus and in plants. The influence of the sympathetic on the motion of the blood in the arteries and veins, and on the functions of the absorbents, on digestion, and on the evolution of animal heat are considered. Under a second head the excitants of the ganglionic system are reviewed, and especially the influence which the gases contained in the blood exercise upon them. The following passage will give the reader an idea of Dr. Geigel's views and method.

"Since we know that the blood cannot be vitalized without a nervous system, since we know also that the action of the nervous system cannot be developed without the blood, and, consequently that neither can exhibit life, or develop vital phenomena without the other; further, since we see that all matters received into the blood act variously, partly on the blood, partly on the nervous system, so matters must absolutely exist in the blood, which shall sometimes exalt, sometimes depress the functions of the nervous system, or produce both results according to the relations which they bear to the blood when received into it. These matters according to my views are the gases contained in the blood. The blood contains, according to the researches of chemists, oxygen, hydrogen, nitrogen, and carbon, the latter generally in combination with oxygen or carbonic acid." (p. 55.)

Dr. Geigel then details experiments showing the relative quantities of these present in arterial and venous blood respectively, and their operations on the nervous system. He infers that carbon paralyses the ganglionic system, but carbonic acid excites the susceptibility of the sensitive nerves. Nitrogen excites the sensitive system, while hydrogen paralyses it, or at least diminishes the irritability of the brain and nerves of sense, acting on the cerebral system as carbon acts on the ganglionic. Oxygen, however, is the primary excitant of the ganglionic system, increasing its activity and irritability. Nitrogen combined with oxygen, as the nitrous oxide, or with hydrogen as ammonia, increases and maintains the activity of the sensitive nerves.

Dr. Geigel then considers the excretory organs as the channels through which these various gases are removed in a solid form from the blood, and then discusses the action of the brain on the ganglionic system, and on the organs of the body generally. In the latter section a variety of physiological details are entered into which we cannot even enumerate.

In the section on the influence of the ganglia on the brain, Dr. Geigel develops a theory of temperaments. The gases in the blood perform a leading part in marking the different temperaments. If oxygen be present in a quantity above par, it determines the sanguineo-choleric temperament; if carbon, we have the melancholic or hypochondriacal. In the next section we have the pathology of fever, and inflammation, discriminating pulmonary inflammation, as it is connected with arterial or venous blood. As the function of the lungs has an important bearing on the changes in the blood, the physiology of sanguification, respiration, and circulation, is minutely considered, especially with reference to the