dies, will equally apply to the bones and organs of the other side, ex- lyzed and the other not. But this is not universally so as respects the viscera under the surface; thus the lung on one side of the thorax is larger than on the other, and the heart is more on the left side, and the liver and other viscera of the abdomen are not by any means equally distributed in each half of the frame. We shall find that many of the nerves, of which there are usually pairs, actually cross from one side to the other. CHAP. II. COMPO- &c. INTO In order to assist in ascertaining the exact local situations and state of DIVISIONS. a particular organ or part that is supposed to be diseased or injured, so REGIONS. as to apply appropriate remedies, it has long been the usage of medical practitioners to divide many external parts of the human frame, and especially the thorax or chest, and the abdomen, into certain parts, technically called Regions, by certain arbitrary and ideal lines and cross lines constituting compartments and divisions; and by long practice and observation these have been rendered so exact and certain, that it is considered that any able physician or surgeon may thereby so accurately know what particular organ, or part of an organ, is under any particular point on the surface, as to be able with a stiletto, or other small pointed instrument, immediately to perforate and touch it without the least deviation, and also to discover, by inspection or sound, the state of inflammation or of other disease or injury.(0) It has been observed, that by a proper examination of parts of the surface in these regions, the state of certain diseases or injuries may be well ascertained, more especially in the thorax and abdomen. This mode of discovery is technically termed Exploration (from the verb exploro, to examine.) In two very valuable modern publications, these regions, especially as regards the chest and abdomen, have been explicitly defined, and the use of such exploration clearly and practically shown; but it is to be regretted that there is still considerable discrepancy amongst the writers upon the subject.(p) Mr. Bell has ridiculed, as we have seen, the extension of these fanciful or ideal subdivisions of Regions to parts not capable of, or at least not requiring, such arrangement, observing what must be the surprise of any well educated young man when he reads in those books which he must study, of the Regions of the elbow, or thumb, or forefinger; (q) and if an anatomist understands such things with difficulty, how distressing must they be to the student? But we nevertheless find the terms still practically continued and extended in very learned works, to every minute part of the frame, especially as regards the muscles, (r) and not confined to the tho (m) 3 Par, & Fon. 33. 10 Harg. State Trials, 29. (n) By observing this law of nature, murder by another person, instead of felo de se has been detected, as by the discovery of the impression of a bloody left hand upon the left arm of the deceased. So the murderer Patch was convicted, partly by the proof that the loaded pistol must have been fired by a left handed person, and that Patch was left handed. (0) See 3 Bell, Anat. 255: 3 Good, 201 to 207; S. Cooper, Dict. tit. Auscultation, (p) See plate in the excellent article (q) 2 Bell, Anat. Introd. xxiv. xxv. ante, 10. (r) See Quain, El. 2d edit. Table of Contents, xxiii. to xxv., and pages in context, 239 to 385. CHAP. II. rax and abdomen, but extended to the epicranial, palpebral, nasal, maxII. THE illary, auricular, orbital and cervical regions of the head and neck, and so on downward in every part of the frame, and notwithstanding Mr. NENT MA- Bell's observations, we have still repeated the external, internal, and COMPO TERIALS, &c. ence to the centre. middle palmar regions of the hand. Hence, even a practitioner in the law should be acquainted with these regions so that he may be enabled duly to examine a medical witness. The practical application of the knowledge of regions will hereafter be more fully considered when we describe the various modes of discovering and ascertaining disorders and injuries, and plates will then be given showing the regions as described by Dr. Forbes and other able physiologists. (s) But by examining some of the references it will be seen that the learned do not altogether agree. Physiognomists divide the face into three ideal divisions and term them regions; the upper part being that of the intellectual life, the middle the moral, and the lower part of the animal life; and these are supposed to be analogous to the head, chest, and abdomen, and are respectively in the notions of physiognomists the seat of three corresponding classes of faculties.(t) Whilst the Phrenologists, more properly cranioscopists, divide the entire skull into five regions.(u) The utility, if any, of these latter divisions, will be better considered hereafter when examining the head and its parts; they are here merely mentioned to show the entire outline of the different divisions. Progress of It is here important to notice two laws of organized nature, termed by growth M. Serres, Zoognie, which not only regulate the original formation of from the the organs, or different parts, but also in case of loss or injury, as of fraccircumfer- tured bones or muscles, the manner in which they are reproduced. M. Serres states, that these laws are two in number, and are to be denominated the laws of symmetry, and that of conjugaison, the first of these designated as "le principe du double developpement des organes," the second, as "le principe de leur reunion."(v) Unorganized bodies, such as crystals, commence with a central nucleus, and are enlarged by attraction and the deposition of layers on its surface, and, therefore, grow from the centre to the circumference. But contrary to the general supposition, it is otherwise in organized bodies, which increase and enlarge from the circumference to the centre, and not by any law of attraction, and the outward form is as it were sketched concurrently with the production of the inner parts, and, indeed, is completed before many of them have made much progress in their development;() whilst, on the contrary, diseases grow, or have a tendency from the centre to the surface.(y) Each organ of the animal function is in the first instance double, its parts being placed laterally with regard to one another; but as the process of nutrition advances, they gradually thicken and enlarge, and approach and unite, so as to form organs, usually termed single, from their appearance on examination after their growth has been completed.(z) The process of ossification, for instance, proceeds from the circumference towards the centre. Thus the lateral parts of the cranial bones are formed first, and their extension proceeds from the sides, beginning at the prominent parts (s) See the plate Cyclop. Prac. Med. (t) 3 Bost. Phy. 220. (v) Serres, Anatomie Comparée, du aux Vertebrés; and see extracts, 3 Bost. 297 to 303.. (x) 1 Dunglison, Phy. 6. (y) See instances and exceptions, S. Coop. Dict. tit. Ulceration. (z) Id. ibid. and El. Blum; 53; 3. Bost 297, centre to the surface. MA TERIALS, &c. of the parietes and frontal bones, and then extends to the central line. (2) CHAP. II. Each vertebra of the spinal column, and therefore the whole pillar itself, II. THE even including the sacrum, is composed of two parts, which finally become, COMPOas it were, soldered together along the median line. In considering the NENT progress of ossification, M. Serres observes, that if we watch the gradual formation of the bones we shall perceive that the external parts are first visible, and that the interior and central parts are composed of productions from these, and that it is in consequence of this progress of ossification that the double development of the single parts which compose the centre of the skeleton is effected, and hence arises the law of symmetry, by which, with a few exceptions, the two sides correspond with each other; and as respects the law of conjugaison he points out its operation in the formation of the various cavities, holes and canals which are found in the bones, and which he supposes to be produced by a union of what were originally separate parts, and he concludes, that by the application of these principles what we may consider as the mechanical process by which the solid frame-work of the body is progressively developed may be explained, and the relation detected which its component parts bear to each other. (a) This principle prevails in all cases and in all parts of the entire structure, (b) whether the structure consists of a simple tube, as a blood vessel, or a muscle, or a nerve. The course of the intestinal canal is at first marked out by two flat bands running along its entire length; these unite in front, so as to form a groove, the margins of which finally arch in and complete the tube. In this way the Trachea or wind-pipe, larynx, œsophagus and aorta are formed. The same principle obtains also in the Muscular System, the lateral parts being produced before those at the middle line. The Nervous System in its development obeys the same law, and may be said to begin in its formation and growth where it has hitherto been thought to terminate, and vice versa. (c) It is stated by several authors, that also in Reproductions of parts destroyed by laceration or ulceration, the renovation is first on the margins of the skin, and then the chasm is gradually filled up from those margins towards the centre, and this is certainly so when an ulcer is in a state of healing. (d) It has been observed that these facts claim in an especial manner the anatomist's attention; they point out the marked line of distinction which exists between organized and unorganized bodies; the latter being universally admitted to be produced in the first instance by an aggregation of particles of matter regulated by the laws of chemical attraction, and subsequently increased by a deposition of similar particles round the central nucleus, and the development and increase proceeds in a course precisely the reverse of that in organized matter, where we have seen it begins at the circumference and gradually extends to the centre, and which must evidently be regulated by laws differing altogether from those which direct the formation of masses of inert matter. (e) The appearance of monsters, and erroneously supposed hermaphrodites or other mal-formed children, and even a hare lip, or fissured palate, has been ascertained to be attributable to some irregularity in the progress (z) [This is not strictly correct, as the commencement and progress of ossification vary in the different bones. 1 Horn. Anat. 68 to 71.] (a) M. Serres, Anatomie Comparée du Cerveau dans les quatre Classes des Animaux Vertebrés; and see 3 Bost. 297, 299. (b) 3 Bost. 299. (c) 3 Bost. 300; Quain's El. 2d edit. 19, more fully. 88. (d) S. Coop. Dict. tit. Ulceration. CHAP. II. of growth from the circumference to the centre, and a want of proper II. THE proportions and union between the lateral parts. (ƒ) COMPONENT MA TERIALS, Conse quence of imperfection in an organ or part. It has been observed, that in the animal functions a harmony of action in &c. every organ or in each half of the organ, is indispensable to perfection when both organs or sides act together, and that if such harmony do not occur, it is better for one organ or one half to act alone. (g) This certainly appears true as respects the eye and ear, and even the brain. But it certainly does not hold good in the actions of the voluntary muscles, nor in the operation of the brain or spinal marrow in willing those actions. From the duplicity of the organs it also happens that one side may cease to act without detriment to the functions of the other. While in the vital or organic functions no harmony of action is possible, and the derangement of any one part of an organ generally affects the whole; as an obstruction in the colon, disturbs the functions of all the alimentary canal. And, at least, much of the comfort of life altogether depends upon an harmonious co-operation of the whole of the organs as well as the functions.(h) III. Essen III. THE ESSENTIAL PROPERTIES AND VITAL POWERS, &c.(i) We have now to consider the effect produced upon the aggregate of all tial Proper- the foregoing materials when thus formed into organs and functions, by the Vital and other Properties and Powers with which the living frame is endowed. ties, and Vital Powers, &c. First, Life defined, and the tion considered. Here the first question is, What is Life? or, in what consist vitality and the power of resisting putrefaction or decomposition? This has been generally termed the vital principle, but, as shown by Dr. Bostock, that power of term has been used without any definite or appropriate signification, and resisting seems rather calculated to mislead and to induce an erroneous supposition putrefac- that it is some unknown independent material agent, than to elucidate.(k) By the term Life or Vitality is generally meant the power of organized matter to preserve its particles in such chemical relations as to prevent other chemical relations from inducing disorganization, to increase or decrease by internal appropriation and separation, to produce peculiar matters for its own purposes, to preserve in some measure a temperature distinct from that of the surrounding medium,(7) to move certain parts of itself sensibly (as muscles) or insensibly as the capillaries independently of mere impulse, attraction, or repulsion.(m) What is it in the human frame when living that prevents the decomposition and putridity of the materials which we have just considered, and which we know immediately ensue after death? The answer has usually been,it is the Vital power; but until of late,no philosophical definition of what that power is, has been given. Life is nothing more than the preservation of the body, which is composed of materials naturally corruptible, but without the occurrence of corruption. It is the opposite of putridity. Vitality is that power which, during life, opposes the chemical affinities which would otherwise induce immediate (f) Quain's El. 25; Geoffroy St. Hilaire, Philosophie Anatomique, vol. 2; Amer. Cyclop. Prac. Med. tit. Acephalous. El. Blum. 55, 56. El. Blum. 55, 56; 4 Good, 227; 3 (k) 2 Bost. 148 to 152. (1) El. Blum. 61; 2 Bost. 192. (m) Thus the internal Temperature of man is usually about 96 or 98 degrees, and which is also the degree of heat of the blood at the centre, or under the armpit, and termed blood heat, whilst (at least in England) at the same time the external atmosphere is usually from 50 to 70, and universally under the temperature of man, 2 Bost. 192, &c. As to Animal Heat and Temperature, see post. Chap, on Respiration. putrefaction. (1) The power of the living muscle so far exceeds the force CHAP. II. of gravity, that it will readily raise the same weight which, if the muscle III. THE were dead, would break it asunder.(m) But the foregoing observations afford no satisfactory answer to the question, In what does the Vital power consist? We may safely answer negatively, that it is not, as has been supposed by some, an unknown independent material agent; but that it is to be attributed principally to the several consequences of respiration, and to the perpetual animal heat and changes occasioned by continued fresh inspiration and expiration, which introduce new wholesome materials, and carry off from the blood those which are noxious, and occasion incessant motion and change in every part of the frame, and excite the muscles to contractility and perpetual motion, thereby excluding stagnation, and its usual incident putridity.(n) We say principally, because, according to the conception which we are led to entertain of the structure and power of the living body, it is clear that every action which it performs, produces some useful purpose in its economy, and is essential to the perfect existence and well-being of the whole. But there are some principal functions so indispensably essential, that a suspension of their exercise, even for five minutes, would be fatal, and hence they naturally claim principal and primary consideration. Thus in particular it is established, that of all the constituents of the body, the Blood, and especially its red globules, are the most subject to decomposition, and it is accordingly on this that the air is conceived more immediately to act in the process of respiration, by the removal of superfluous carbon, and introducing fresh oxygen, and thereby carrying off the noxious parts, and introducing a perpetual renewal of wholesome qualities, and occasioning the circulation of renovated blood, and also those secretions and excretions which remove the effete and noxious matter. This is one of the principal preventions of decomposition and corruption, and the principal cause of vitality.(0) It has been usually considered, that there are distinct orders of the vital powers, according to the variety of the phenomena by which they are manifested. These are threefold, 1st, Organic formation and increase; 2dly, Motion in the parts when formed; 3dly, Sensation, from the motion of certain similar parts.(p) The two specific powers that distinguish living from dead matter, are spontaneous motion and sensation; the first is confined entirely to the muscles, while the latter is equally confined to the brain and nerves. When a nerve is acted upon in such a manner as that its appropriate power is excited, motion is not necessarily produced, nor any other visible change; but the animal feels: on the other hand, there are many cases in which motion is produced, that is unattended with sensation; of this kind are most of the minute operations that compose the internal functions (as the abdomen,) of which, in a state of health, we are perfectly unconscious, and which are only known to us by their effects. These two powers, therefore, motion and sensation, although in a great number of instances they are connected together, being reciprocally the cause of each other, are not however necessarily connected, for either of them may exist separately, and when they are connected, it is not in any regular proportion. We conclude, therefore, that it is the office of the Nervous System to produce sensation; but with respect to the way or mode in which this is accomplished, or the succession of changes by (1) El. Blum. 28, n. (b) cites Stahl and J. Junker, as to putrefaction, and what contributes towards or retards its progress; see also Dr. Turner, El. Chem. 578, (m) El. Blum. 281; 1 Horn. Anat. 381. (n) 2 Bost. 148 to 152; Jackson's Prin. Med. 98, &c.; and post, 46, 47. (0) 2 Bost. 148 to 152; as to azote, ante, 26, note (1;) and Quain's El. 2d edit. 27. (p) El. Blum. 29, 30; Jackson's Prin. Med. 11, &c. ESSENTIAL TIES, &c. |