Part 15 (1/2)

The problem of force meets us everywhere, and I prefer to encounter it in the world of physical phenomena before reaching that of living actions. It is only the name for the incomprehensible cause of certain changes known to our consciousness, and a.s.sumed to be outside of it. For me it is the Deity Himself in action.

I can therefore see a large significance in the somewhat bold language of Burdach: ”There is for me but one miracle, that of infinite existence, and but one mystery, the manner in which the finite proceeds from the infinite. So soon as we recognize this incomprehensible act as the general and primordial miracle, of which our reason perceives the necessity, but the manner of which our intelligence cannot grasp, so soon as we contemplate the nature known to us by experience in this light, there is for us no other impenetrable miracle or mystery.”

Let us turn to a branch of knowledge which deals with certainties up to the limit of the senses, and is involved in no speculations beyond them.

In certain points of view, HUMAN ANATOMY may be considered an almost exhausted science. From time to time some small organ which had escaped earlier observers has been pointed out,--such parts as the tensor tarsi, the otic ganglion, or the Pacinian bodies; but some of our best anatomical works are those which have been cla.s.sic for many generations.

The plates of the bones in Vesalius, three centuries old, are still masterpieces of accuracy, as of art. The magnificent work of Albinus on the muscles, published in 1747, is still supreme in its department, as the constant references of the most thorough recent treatise on the subject, that of Theile, sufficiently show. More has been done in unravelling the mysteries of the fasciae, but there has been a tendency to overdo this kind of material a.n.a.lysis. Alexander Thomson split them up into cobwebs, as you may see in the plates to Velpeau's Surgical Anatomy. I well remember how he used to shake his head over the coa.r.s.e work of Scarpa and Astley Cooper,--as if Denner, who painted the separate hairs of the beard and pores of the skin in his portraits, had spoken lightly of the pictures of Rubens and Vandyk.

Not only has little been added to the catalogue of parts, but some things long known had become half-forgotten. Louis and others confounded the solitary glands of the lower part of the small intestine with those which ”the great Brunner,” as Haller calls him, described in 1687 as being found in the duodenum. The display of the fibrous structure of the brain seemed a novelty as shown by Spurzheim. One is startled to find the method antic.i.p.ated by Raymond Vieussens nearly two centuries ago. I can hardly think Gordon had ever looked at his figures, though he names their author, when he wrote the captious and sneering article which attracted so much attention in the pages of the ”Edinburgh Review.”

This is the place, if anywhere, to mention any observations I could pretend to have made in the course of my teaching the structure of the human body. I can make no better show than most of my predecessors in this well-reaped field. The nucleated cells found connected with the cancellated structure of the bones, which I first pointed out and had figured in 1847, and have shown yearly from that time to the present, and the fossa ma.s.seterica, a shallow concavity on the ramus of the lower jaw, for the lodgment of the ma.s.seter muscle, which acquires significance when examined by the side of the deep cavity on the corresponding part in some carnivora to which it answers, may perhaps be claimed as deserving attention. I have also pleased myself by making a special group of the six radiating muscles which diverge from the spine of the axis, or second cervical vertebra, and by giving to it the name stella musculosa nuchaee. But this scanty catalogue is only an evidence that one may teach long and see little that has not been noted by those who have gone before him. Of course I do not think it necessary to include rare, but already described anomalies, such as the episternal bones, the rectus sternalis, and other interesting exceptional formations I have encountered, which have shown a curious tendency to present themselves several times in the same season, perhaps because the first specimen found calls our attention to any we may subsequently meet with.

The anatomy of the scalpel and the amphitheatre was, then, becoming an exhausted branch of investigation. But during the present century the study of the human body has changed its old aspect, and become fertile in new observations. This rejuvenescence was effected by means of two princ.i.p.al agencies,--new methods and a new instrument.

Descriptive anatomy, as known from an early date, is to the body what geography is to the planet. Now geography was pretty well known so long ago as when Arrowsmith, who was born in 1750, published his admirable maps. But in that same year was born Werner, who taught a new way of studying the earth, since become familiar to us all under the name of Geology.

What geology has done for our knowledge of the earth, has been done for our knowledge of the body by that method of study to which is given the name of General Anatomy. It studies, not the organs as such, but the elements out of which the organs are constructed. It is the geology of the body, as that is the general anatomy of the earth. The extraordinary genius of b.i.+.c.hat, to whom more than any other we owe this new method of study, does not require Mr. Buckle's testimony to impress the pract.i.tioner with the importance of its achievements. I have heard a very wise physician question whether any important result had accrued to practical medicine from Harvey's discovery of the circulation. But Anatomy, Physiology, and Pathology have received a new light from this novel method of contemplating the living structures, which has had a vast influence in enabling the pract.i.tioner at least to distinguish and predict the course of disease. We know as well what differences to expect in the habits of a mucous and of a serous membrane, as what mineral substances to look for in the chalk or the coal measures. You have only to read Cullen's description of inflammation of the lungs or of the bowels, and compare it with such as you may find in Laennec or Watson, to see the immense gain which diagnosis and prognosis have derived from general anatomy.

The second new method of studying the human structure, beginning with the labors of Scarpa, Burns, and Colles, grew up princ.i.p.ally during the first third of this century. It does not deal with organs, as did the earlier anatomists, nor with tissues, after the manner of b.i.+.c.hat. It maps the whole surface of the body into an arbitrary number of regions, and studies each region successively from the surface to the bone, or beneath it. This hardly deserves the name of a science, although Velpeau has dignified it with that t.i.tle, but it furnishes an admirable practical way for the surgeon who has to operate on a particular region of the body to study that region. If we are buying a farm, we are not content with the State map or a geological chart including the estate in question. We demand an exact survey of that particular property, so that we may know what we are dealing with. This is just what regional, or, as it is sometimes called, surgical anatomy, does for the surgeon with reference to the part on which his skill is to be exercised. It enables him to see with the mind's eye through the opaque tissues down to the bone on which they lie, as if the skin were transparent as the cornea, and the organs it covers translucent as the gelatinous pulp of a medusa.

It is curious that the j.a.panese should have antic.i.p.ated Europe in a kind of rude regional anatomy. I have seen a manikin of j.a.panese make traced all over with lines, and points marking their intersection. By this their doctors are guided in the performance of acupuncture, marking the safe places to thrust in needles, as we buoy out our s.h.i.+p-channels, and doubtless indicating to learned eyes the spots where incautious meddling had led to those little accidents of s.h.i.+pwreck to which patients are unfortunately liable.

A change of method, then, has given us General and Regional Anatomy.

These, too, have been worked so thoroughly, that, if not exhausted, they have at least become to a great extent fixed and positive branches of knowledge. But the first of them, General Anatomy, would never, have reached this positive condition but for the introduction of that, instrument which I have mentioned as the second great aid to modern progress.

This instrument is the achromatic microscope. For the history of the successive steps by which it became the effective scientific implement we now possess, I must refer you to the work of Mr. Quekett, to an excellent article in the ”Penny Cyclopaedia,” or to that of Sir David Brewster in the ”Encyclopaedia Britannica.” It is a most interesting piece of scientific history, which shows how the problem which Biot in 1821 p.r.o.nounced insolvable was in the course of a few years practically solved, with a success equal to that which Dollond had long before obtained with the telescope. It is enough for our purpose that we are now in possession of an instrument freed from all confusions and illusions, which magnifies a thousand diameters,--a million times in surface,--without serious distortion or discoloration of its object.

A quarter of a century ago, or a little more, an instructor would not have hesitated to put John Bell's ”Anatomy” and Bostock's ”Physiology”

into a student's hands, as good authority on their respective subjects.

Let us not be unjust to either of these authors. John Bell is the liveliest medical writer that I can remember who has written since the days of delightful old Ambroise Pare. His picturesque descriptions and bold figures are as good now as they ever were, and his book can never become obsolete. But listen to what John Bell says of the microscope:

”Philosophers of the last age had been at infinite pains to find the ultimate fibre of muscles, thinking to discover its properties in its form; but they saw just in proportion to the gla.s.ses which they used, or to their practice and skill in that art, which is now almost forsaken.”

Dr. Bostock's work, neglected as it is, is one which I value very highly as a really learned compilation, full of original references. But Dr. Bostock says: ”Much as the naturalist has been indebted to the microscope, by bringing into view many beings of which he could not otherwise have ascertained the existence, the physiologist has not yet derived any great benefit from the instrument.”

These are only specimens of the manner in which the microscope and its results were generally regarded by the generation just preceding our own.

I have referred you to the proper authorities for the account of those improvements which about the year 1830 rendered the compound microscope an efficient and trustworthy instrument. It was now for the first time that a true general anatomy became possible. As early as 1816 Trevira.n.u.s had attempted to resolve the tissues, of which b.i.+.c.hat had admitted no less than twenty-one, into their simple microscopic elements. How could such an attempt succeed, Henle well asks, at a time when the most extensively diffused of all the tissues, the areolar, was not at all understood? All that method could do had been accomplished by b.i.+.c.hat and his followers. It was for the optician to take the next step. The future of anatomy and physiology, as an enthusiastic micrologist of the time said, was in the hands of Messrs. Schieck and Pistor, famous opticians of Berlin.

In those earlier days of which I am speaking, all the points of minute anatomy were involved in obscurity. Some found globules everywhere, some fibres. Students disputed whether the conjunctiva extended over the cornea or not, and worried themselves over Gaultier de Claubry's stratified layers of the skin, or Breschet's blennogenous and chromatogenous organs. The dartos was a puzzle, the central spinal ca.n.a.l a myth, the decidua clothed in fable as much as the golden fleece. The structure of bone, now so beautifully made out,--even that of the teeth, in which old Leeuwenhoek, peeping with his octogenarian eyes through the minute lenses wrought with his own hands, had long ago seen the ”pipes,”

as he called them,--was hardly known at all. The minute structure of the viscera lay in the mists of an uncertain microscopic vision. The intimate recesses of the animal system were to the students of anatomy what the anterior of Africa long was to geographers, and the stories of microscopic explorers were as much sneered at as those of Bruce or Du Chailly, and with better reason.

Now what have we come to in our own day? In the first place, the minute structure of all the organs has been made out in the most satisfactory way. The special arrangements of the vessels and the ducts of all the glands, of the air-tubes and vesicles of the lungs, of the parts which make up the skin and other membranes, all the details of those complex parenchymatous organs which had confounded investigation so long, have been lifted out of the invisible into the sight of all observers. It is fair to mention here, that we owe a great deal to the art of minute injection, by which we are enabled to trace the smallest vessels in the midst of the tissues where they are distributed. This is an old artifice of anatomists. The famous Ruysch, who died a hundred and thirty years ago, showed that each of the viscera has its terminal vessels arranged in its own peculiar way; the same fact which you may see ill.u.s.trated in Gerber's figures after the minute injections of Berres. I hope to show you many specimens of this kind in the microscope, the work of English and American hands. Professor Aga.s.siz allows me also to make use of a very rich collection of injected preparations sent him by Professor Hyrtl, formerly of Prague, now of Vienna, for the proper exhibition of which I had a number of microscopes made expressly, by Mr. Grunow, during the past season. All this ill.u.s.trates what has been done for the elucidation of the intimate details of formation of the organs.

But the great triumph of the microscope as applied to anatomy has been in the resolution of the organs and the tissues into their simple const.i.tuent anatomical elements. It has taken up general anatomy where b.i.+.c.hat left it. He had succeeded in reducing the structural language of nature to syllables, if you will permit me to use so bold an image. The microscopic observers who have come after him have a.n.a.lyzed these into letters, as we may call them,--the simple elements by the combination of which Nature spells out successively tissues, which are her syllables, organs which are her words, systems which are her chapters, and so goes on from the simple to the complex, until she binds up in one living whole that wondrous volume of power and wisdom which we call the human body.

The alphabet of the organization is so short and simple, that I will risk fatiguing your attention by repeating it, according to the plan I have long adopted.

A. Cells, either floating, as in the blood, or fixed, like those in the cancellated structure of bone, already referred to. Very commonly they have undergone a change of figure, most frequently a flattening which reduces them to scales, as in the epidermis and the epithelium.

B. Simple, translucent, h.o.m.ogeneous solid, such as is found at the back of the cornea, or forming the intercellular substance of cartilage.