« AnteriorContinua »
gradually lessens towards the superior parts. Where most engorged, the part still retains some crepitation, and the incised surfaces are never granulated, even when the congestion is so great as to destroy the spongy character of the lung. By washing, we can, in every case, remove all the blood, and restore the lung to that sort of flaccidity which it possesses when compressed by a pleuritic effusion. The engorgement of hæmoptysis, on the contrary, is accurately circumscribed, very deose, dark-red or brown, granulated, and almost dry when incised, and grows pale by washing, but without losing any part of its consistence." P. 64.
Whatever may be the severity of the case, resolution seems to take place with considerable facility, since we find a great many instances of cure after yery severe hæmoptysis. The above is the condition of parts in all these severe cases; but when the symptoms are moderate, and the hæmorrhage slight, the only morbid alteration of structure is a reddening and thickening of the bronchial membrane, which, in these cases, seems to permit the transudation of the blood.
Therapeutical matters enter not into the composition of this valuable work; but we may just remark, en passant, that we have found practitioners in this country too timorous in respect to the exhibition of superacetate of lead and opium in hæmoptysis. We have happened to be much in the way of this disease, and we have found such decided benefit from the combination above mentioned, and that in large doses, that we beg to impress the circumstance on the memory of our younger brethren. Without having so accurate an idea of the real pathology of the disease as Laennec has since imparted, we had long been convinced that the blood came from the capillary vessels, and consequently that those remedies which are known to have an influence on the capillary system, were indicated.
We have often seen men bled day after day, and take digitalis, infusion of roses, and sulphuric acid, in hæmoptysis, withont materially lessening the flow from the lungs; while, on the other hand, a moderate bleeding, followed by superacetate of lead and opium, has restrained effectually some of the most alarming discharges of blood which we ever witnessed.
But we must now reluctantly take leave of Dr. Laennec and his translator. To the former we have often paid the tribute of our respect for his talents, and unwearied exertions in the science of pathology. In Dr. Forbes the public has a physician of native genius and acquired knowledge the profession, a member of zeal, honour, and integrity.
VIII. On the Nerves ; giving an Account of some Experiments on
their Structure and Functions, which lead to a new Arrangement of the System. By CHARLES Bell, Esq. (From the Philosophical Transactions.) Quarto, pp. 30. One Plate. London, 1821.
Without physiology-that is, without a perfect knowledge of the laws by which the healthy functions of our system are governed, we cannot expect to make much progress in pathology. Every person, therefore, who elucidates a known, or discovers a new law in the animal economy, contributes his mite to the advancement of the science of medicine-even if that law should not appear to bear on any point of pathology or practice at the time.* No man, in this country,
. works harder in unravelling those mysteries of the nervous system which puzzles our senses, than the present distinguished teacher in the venerable school of the Hunters.
Mr. Bell remarks, that when the physiologist sees two distinct nerves ramifying over the face-three nerves, from different sources, going to the tongue-four to the throat-and nerves in most perplexing intricacy to the neck; when he
; finds one nerve with numerous ganglia upon it, and another without them—when, in short, after a minute dissection of the nervous system, he finds a mesh, or network, spreading every where, it is not surprising that the seeming intricacy and confusion should make him, in despair, resign inquiry. Mr. Bell, however, by long dissection and study, has been able gradually to decipher some of the abstruse language of the nervous system, and hopes, sooner or later, to come to a comprehension of the whole.
The present inquiry is limited to the nerves of respiration, which our author thinks, form a system of great extent, comprehending all the nerves which serve to combine the muscles employed in the act of breathing and speaking. Tranquil breathing gives a very limited view of the respiratory muscles. But if a man be excited by exercise or passion, or by whatever accelerates the pulse, the respiratory action is extended and increased; and, instead of the almost imperceptible motion of the chest, as in common breathing,
* When the air-balloon was first discovered, some one flippantly asked Dr. Franklin what was the use of it? The Doctor answered, in the Socratic manner, by asking another question :-What is the use of a new-born infantil may become a man."
the shoulders are raised at each inspiration, the muscles of the throat and neck are violently drawn, and the lips and nostrils move in time with the general action. If he does not breathe through his mouth, the nostrils expand, and fall in time with the rising and falling of the chest, whilst the curious apparatus of cartilages and muscles of the pose, are as regularly in action as the levator and depressor muscles of the ribs.
“It is quite obvious, that some hundred muscles thus employed in the act of breathing, or in the common actions of coughing, sneezing, speaking, and singing, cannot be associated without cords cf connexion or affinity, which combine them in the performance of these actions; the nerves which serve this purpose I call respiratory nerves.
Mr. Bell observes, that the nerves of all animals, including man, may be divided into two systems or classes_into those destined for the organization necessary to life and motion in an animal—and those which supply organs superadded as the animal advances in the scale of existence. The nerves of the spine, the tenth or sub-occipital nerve, and the fifth or trigeminus, belong to the simple and symmetrical system.
"All these nerves agree in these essential circumstances ; they have all double origins; they have all ganglia on one of their roots ; they go out laterally to certain divisions of the body ; they do not interfere to unite the divisions of the frame ; they are all muscular nerves, ordering the voluntary motions of the frame ; they are all
; exquisitely sensible ; and the source of the common sensibility of the surfaces of the body : when accurately represented on paper, they are seen to pervade every part ; no part is without them; and yet they are symmetrical and simple as the nerves of the lower animals.
“ If the nerves be exposed in a living animal, those of this class exhibit the highest degree of sensibility; while, on the contrary, nerves not of this original class or system, are comparatively so little sensible, as to be immediately distinguished ; insomuch that the quiescence of the animal suggests a doubt whether they be sensible in any degree whatever. If the fifth nerve and the portio dura of the seventh, be both exposed on the face of a living animal, there will not remain the slighest doubt in the mind of the expe. rimenter which of these nerves bestows sensibility. If the nerve of this original class be divided, the skin and common substance is deprived of sensibility ; but if a nerve not of this class he divided, it in no measure deprives the parts of their sensibility to external impression.” P. 10.
The nerves connecting the iyterual organs of respiration with the sensibilities of remote parts, and with the respiratory muscles, are distinguished from the above by many cir
cumstances. They have not double roots, nor ganglia on their origins. They come off from the medulla oblongata and the upper part of the spinal marrow, and from this origin they diverge to those several remote parts of the frame which are combined in the motion of respiration. These are the nerves which give the appearance of confusion to the dissection, because they cross the others, and go to parts already plentifully supplied from the other system. The following are respiratory nerves, according to their functions.
1. The par vagum, distributed to the larynx, lungs, heart, and stomach, associating these organs together, though they are plentifully supplied with nerves from other sources.
Comparative anatomy would lead us to infer that this nerve is not essential to the stomach, as it does not exist lout where there are heart and lungs to associate with a muscular apparatus of respiration. That the stomach must be associated with the muscu lar apparatus of respiration, as well as the lungs, is obvious, from the consideration of what takes place in vomiting and hiccough, wbich are actions of the respiratory muscles excited by irritation of the stomach." P. 11.
2. Respiratory Nerve of the Face, or portio dura of the seventh. This nerve also goes off from the medulla oblongata, spreads wide on the face, and on it solely depend all those motions of the nostrils, lips, and face generally (as will presently be shown) which accord with the motions of the chest in respiration. By the division of this nerve the face is deprived of its consent with the lungs, and of all expression of motion.
3. Superior Respiratory Nerve of the trunk, or spinal accessory, which has puzzled physiologists on account of the singular course which it pursues. After arising from the upper part of the spinal marrow, in a line with the roots of the other respiratory nerves, it passes into the skull, and comes out with the par vagum, descending upon the neck, supplying muscles of the shoulder already profusely supplied with nerves from other sources. This nerve controls the operations of the muscles of the neck and shoulder in their office as respiratory muscles, when by lifting the shoulders they take the load from the chest, and give freedom to the expansion of the thorax. When this nerve is cut across in experiments, the muscles of the shoulder, which are in action as respiratory muscles, cease their co-operation, but remain capable of voluntary actions.
4. The internal Respiratory Nerve-phrenic or diaphragmatic. This is the only nerve of the system usually considered respiratory. Its origin, course, and destination are familiar to all. But there is another nerve much resembling it, which has been entirely overlooked. It is
5. The external Respiratory Nerve, which has its origin with the preceding nerve, coming from the cervical vertebræ, and being conuiected with the phrenic nerve. It runs down the neck, crosses the cervical and axillary nerves, passes through the axilla, and arrives ou "the outside of the ribs, where, it is hardly necessary to observe, the muscles are already supplied by nerves coming out betwixt the ribs from the system of regular nerves.
“ These four last mentioned nerves govern the muscles of the face, neck, shoulders, and chest, in the actions of exciied respiration, and are absolutely necessary to speech and expression. But there are other nerves of the same class which go to the tongue, throat, and windpipe, no less essential to complete the act of respiration. These are the glosso pharyngeal nerve, the lingual, or ninth of Willis, and the branches of the par vagum to the supe. rior and inferior larynx." P. 13.
The nerves of the face afford the best illustration of the foregoing doctrines. The human countenance pertornis many functions-mastication, breatbing, natural voice and speech, expression of the passions and emotions.
Trigeminus. In all animals that have a stomach, with palpi or tentacula to embrace their food, the rudiments of this nerve are to be observed. From the nerve that comes off from the anterior ganglion of the leech, and which supplies its mouth, we may trace up through the gradations of animals a nerve of taste and manducation, until we arrive at the complete distribution of the fifth or trigeminus in'men. It comes off from the base of the brain, in so peculiar a situation as to receive roots froin the medullary process of the cerebrum and cerebellum. It has a ganglion near its origio. This nerve, as will be shown, serves for taste, motion, and common sensibility in the tongue, jaws, and face.
Portio Dura of the 7th Pair. This nerve does not exist, except where there is some consent of motiops established betwixt the face and the respiratory organs. It arises close to the nodus cerebri, in a line with the roots of the other respiratory nerves. While within the temporal bone two cords of communication are formed with the branches of the 5th nerve the vidian and corda tympani. By these commu