In common parlance, we understand by an egg something of the nature of a hen's egg, a mass of yolk surrounded with white and inclosed in a shell. But to the naturalist, the envelopes of the egg, which vary greatly in different animals, are mere accessories, while the true egg, or, as it is called, the ovarian egg, with which the life of every living being begins, is a minute sphere, uniform in appearance throughout the Animal Kingdom, though its intimate structure is hardly to be reached even with the highest powers of the microscope. Some account of the earlier stages of growth in the egg may not be uninteresting to my readers. I will take the egg of the Turtle as an illustration, since that has been the subject of my own especial study; but, as I do not intend to carry my remarks beyond the period during which the history of all vertebrate eggs is the same, they may be considered of more general application.
It is well known that all organic structures, whether animal or vegetable, are composed of cells. These cells consist of an outside bag inclosing an inner sac, and within that sac there is a dot. The outer bag is filled with semi-transparent fluid, the inner one with a perfectly transparent fluid, while the dot is dark and distinct. In the language of our science, the outer envelope is called the Ectoblast, the inner sac the Mesoblast, and the dot the Entoblast. Although they are peculiarly modified to suit the different organs, these cells never lose this peculiar structure; it may be traced even in the long drawn-out cells of the flesh, which are like mere threads, but yet have their outer and inner sac and their dot,—at least while forming.
In the Turtle the ovary is made up of such cells, spherical at first, but becoming hexagonal under pressure, when they are more closely packed together. Between these ovarian cells the egg originates, and is at first a mere granule, so minute, that, when placed under a very high magnifying power, it is but just visible. This is the incipient egg, and at this stage it differs from the surrounding cells only in being somewhat darker, like a drop of oil, and opaque, instead of transparent and clear like the surrounding cells. Under the microscope it is found to be composed of two substances only: namely, oil and albumen. It increases gradually, and when it has reached a size at which it requires to be magnified one thousand times in order to be distinctly visible, the outside assumes the aspect of a membrane thicker than the interior and forming a coating around it. This is owing not to an addition from outside, but to a change in the consistency of the substance at the surface, which becomes more closely united, more compact, than the loose mass in the centre. Presently we perceive a bright, luminous, transparent spot on the upper side of the egg, near the wall or outer membrane. This is produced by a concentration of the albumen, which now separates from the oil and collects at the upper side of the egg, forming this light spot, called by naturalists the Purkinjean vesicle, after its discoverer, Purkinje. When this albuminous spot becomes somewhat larger, there arises a little dot in the centre,—the germinal dot, as it is called. And now we have a perfect cell-structure, differing from an ordinary cell only in having the inner sac, inclosing the dot, on the side, instead of in the centre. The outer membrane corresponds to the Ectoblast, or outer cell sac, the Purkinjean vesicle to the Mesoblast, or inner cell sac, while the dot in the centre answers to the Entoblast. When the Purkinjean vesicle has completed its growth, it bursts and disappears; but the mass contained in it remains in the same region, and retains the same character, though no longer inclosed as before.
At a later stage of the investigation, we see why the Purkinjean vesicle, or inner sac of the egg, is placed on the side, instead of being at the centre, as in the cell. It arises on that side along which the axis of the little Turtle is to lie,—the opposite side being that corresponding to the lower part of the body. Thus the lighter, more delicate part of the substance of the egg is collected where the upper cavity of the animal, inclosing the nervous system and brain, is to be, while the heavy oily part remains beneath, where the lower cavity, inclosing all the organs of mere material animal existence, is afterwards developed. In other words, when the egg is a mere mass of oil and albumen, not indicating as yet in any way the character of the future animal, and discernible only by the microscope, the distinction is indicated between the brains and the senses, between the organs of instinct and sensation and those of mere animal functions. At that stage of its existence, however, when the egg consists of an outer sac, an inner sac, and a dot, its resemblance to a cell is unmistakable; and, in fact, an egg, when forming, is nothing but a single cell. This comparison is important, because there are both animals and plants which, during their whole existence, consist of a single organic cell, while others are made up of countless millions of such cells. Between these two extremes we have all degrees, from the innumerable cells that build up the body of the highest Vertebrate to the single-celled Worm, and from the myriad cells of the Oak to the single-celled Alga.
But while we recognize the identity of cell-structure and egg-structure at this point in the history of the egg, we must not forget the great distinction between them,—namely, that, while the cells remain component parts of the whole body, the egg separates itself and assumes a distinct individual existence. Even now, while still microscopically small, its individuality begins; other substances collect around it, are absorbed into it, nourish it, serve it. Every being is a centre about which many other things cluster and converge, and which has the power to assimilate to itself the necessary elements of its life. Every egg is already such a centre, differing from the cells that surround it by no material elements, but by the principle of life in which its individuality consists, which is to make it a new being, instead of a fellow-cell with those that build up the body of the parent animal and remain component parts of it. This intangible something is the subtile element that eludes our closest analysis; it is the germ of the immaterial principle according to which the new being is to develop. The physical germ we see; the spiritual germ we cannot see, though we may trace its action on the material elements through which it is expressed.
The first change in the yolk, after the formation of the Purkinjean vesicle, is the appearance of minute dots near the wall at the side opposite the vesicle. These increase in number and size, but remain always on that half of the yolk, leaving the other half of the globe clear. One can hardly conceive the beauty of the egg as seen through the microscope at this period of its growth, when the whole yolk is divided, with the dark granules on one side, while the other side, where the transparent halo of the vesicle is seen, is brilliant with light. With the growth of the egg these granules enlarge, become more distinct, and under the microscope some of them appear to be hollow. They are not round in form, but rather irregular, and under the effect of light they are exceedingly brilliant. Presently, instead of being scattered equally over the space they occupy, they form clusters,—constellations, as it were,—and between these clusters are clear spaces, produced by the separation of the albumen from the oil.
At this period of its growth there is a wonderful resemblance between the appearance of the egg, as seen under the microscope, and the firmament with the celestial bodies. The little clusters or constellations are unequally divided: here and there they are two and two like double stars, or sometimes in threes or fives, or in sevens, recalling the Pleiades, and the clear albuminous tracks between are like the empty spaces separating the stars.
This is no fanciful simile: it is simply true that such is the actual appearance of the yolk at this time; and the idea cannot but suggest itself to the mind, that the thoughts which have been at work in the universe are collected and repeated here within this little egg, which offers us a miniature diagram of the firmament. This is one of the first changes of the yolk, ending by forming regular clusters with a sort of net-work of albumen between, and then this phase of the growth is complete.
Now the clusters of the yolk separate, and next the albumen in its turn concentrates into clusters, and the dark bodies, which have been till now the striking points, give way to the lighter spheres of albumen between which the clusters are scattered. Presently the whole becomes redissolved: these stages of the growth being completed, this little system of worlds is melted, as it were: but while it undergoes this process, the albuminous spheres, after being dissolved, arrange themselves in concentric rings, alternating with rings of granules, around the Purkinjean vesicle. At this time we are again reminded of Saturn and its rings, which seems to have its counterpart here. These rings disappear, and now once more out of the yolk mass loom up little dots as minute as before; but they are round instead of angular, and those nearest the Purkinjean vesicle are smaller and clearer, containing less of oil than the larger and darker ones on the opposite side. From this time the yolk begins to take its color, the oily cells assuming a yellow tint, while the albuminous cells near the vesicle become whiter.
Up to this period the processes in the different cells seem to have been controlled by the different character of the substance of each; but now it would seem that the changes become more independent of physical or material influences, for each kind of cell undergoes the same process. They all assume the ordinary cell character, with outer and inner sac,—the inner sac forming on the side, like the Purkinjean vesicle itself; but it does not retain this position, for, as soon as its wall is formed and it becomes a distinct body, it floats away from the side and takes its place in the centre. Next there arise within it a number of little bodies crystalline in form, and which actually are wax or oil crystals. They increase with great rapidity, the inner sac or mesoblast becoming sometimes so crowded with them, that its shape is affected by the protrusion of their angles. This process goes on till all the cells are so filled by the mesoblast, with its myriad brood of cells, that the outer sac or ectoblast becomes a mere halo around it. Then every mesoblast contracts; the contraction deepens, till it is divided across in both directions, separating thus into four parts, then into eight, then into sixteen, and so on, till every cell is crowded with hundreds of minute mesoblasts, each containing the indication of a central dot or entoblast. At this period every yolk cell is itself like a whole yolk; for each cell is as full of lesser cells as the yolk-bag itself.
When the mesoblast has become thus infinitely subdivided into hundreds of minute spheres, the ectoblast bursts, and the new generations of cells thus set free collect in that part of the egg where the embryonic disk is to arise. This process of segmentation continues to go on downward till the whole yolk is taken in. These myriad cells are in fact the component parts of the little Turtle that is to be. They will undergo certain modifications, to become flesh-cells, blood-cells, brain-cells, and so on, adapting themselves to the different organs they are to build up; but they have as much their definite and appointed share in the formation of the body now as at any later stage of its existence.
We are so accustomed to see life maintained through a variety of complicated organs that we are apt to think this the only way in which it can be manifested; and considering how closely life and the organs through which it is expressed are united, it is natural that we should believe them inseparably connected. But embryological investigations have shown us that in the commencement none of these organs are formed, and yet that the principle of life is active, and that even after they exist, they cannot act, inclosed as they are. In the little Chicken, for instance, before it is hatched, the lungs cannot breathe, for they are surrounded by fluid, the senses are inactive, for they receive no impressions from without, and all those functions establishing its relations with the external world lie dormant, for as yet they are not needed. But they are there, though, as we have seen in the Turtle's egg, they were not there at the beginning. How, then, are they formed? We may answer, that the first function of every organ is to make itself. The building material is, as it were, provided by the process which divides the yolk into innumerable cells, and by the gradual assimilation and modification of this material the organs arise. Before the lungs breathe, they make themselves; before the stomach digests, it makes itself; before the organs of the senses act, they make themselves; before the brain thinks, it makes itself; in a word, before the whole system works, it makes itself; its first office is self-structure.
At the period described above, however, when the new generations of cells are just set free and have taken their place in the region where the new being is to develop, nothing is to be seen of the animal whose life is beginning there, except the filmy disk lying on the surface of the yolk. Next come the layers of white or albumen around the egg, and last the shell which is formed from the lime in the albumen. There is always more or less of lime in albumen, and the hardening of the last layer of white into shell is owing only to the greater proportion of lime in its substance. In the layer next to the shell there is enough of lime to consolidate it slightly, and it forms a membrane; but the white, the membrane, and the shell have all the same quality, except that the proportion of lime is more or less in the different layers.
But, as I have said, the various envelopes of eggs, the presence or absence of a shell, and the absolute size of the egg, are accessory features, belonging not to the egg as egg, but to the special kind of being from which the egg has arisen and into which it is to develop. What is common to all eggs and essential to them all is that which corresponds to the yolk in the bird's egg. But their later mode of development, the degree of perfection acquired by the egg and germ before being laid, the term required for the germ to come to maturity, as well as the frequency and regularity of the broods, are all features varying with the different kinds of animals. There are those that lay eggs once a year at a particular season and then die; so that their existence may be compared to that of annual plants, undergoing their natural growth in a season, to exist during the remainder of the year only in the form of an egg or seed. The majority of Insects belong to this category, as do also our large Jelly-Fishes; many others have a slow growth, extending over several years, during which they reach their maturity, and for a longer or shorter time produce broods at fixed intervals; while others, again, reach their mature state very rapidly, and produce a number of successive generations in a comparatively short time, it may be in a single season.
I do not intend to enter upon the chapter of special differences of development among animals, for in this article I have aimed only to show that the egg lives, that it is itself the young animal, and that the vital principle is active in it from the earliest period of its existence. But I would say to all young students of Embryology that their next aim should be to study those intermediate phases in the life of a young animal, when, having already acquired independent existence, it has not yet reached the condition of the adult. Here lies an inexhaustible mine of valuable information unappropriated, from which, as my limited experience has already taught me, may be gathered the evidence for the solution of the most perplexing problems of our science. Here we shall find the true tests by which to determine the various kinds and different degrees of affinity which animals now living bear not only to one another, but also to those that have preceded them in past times. Here we shall find, not a material connection by which blind laws of matter have evolved the whole creation out of a single germ, but the clue to that intellectual conception which spans the whole series of the geological ages and is perfectly consistent in all its parts. In this sense the present will indeed explain the past, and the young naturalist is happy who enters upon his life of investigation now, when the problems that were dark to all his predecessors have received new light from the sciences of Palaeontology and Embryology.
* * * * *
BLIND TOM
Only a germ in a withered flower,
That the rain will bring out—sometime.
Sometime in the year 1850, a tobacco-planter in Southern Georgia (Perry H. Oliver by name) bought a likely negro woman with some other field-hands. She was stout, tough-muscled, willing, promised to be a remunerative servant; her baby, however, a boy a few months old, was only thrown in as a makeweight to the bargain, or rather because Mr. Oliver would not consent to separate mother and child. Charity only could have induced him to take the picaninny, in fact, for he was but a lump of black flesh, born blind, and with the vacant grin of idiocy, they thought, already stamped on his face. The two slaves were purchased, I believe, from a trader: it has been impossible, therefore, for me to ascertain where Tom was born, or when. Georgia field-hands are not accurate as Jews in preserving their genealogy; they do not anticipate a Messiah. A white man, you know, has that vague hope unconsciously latent in him, that he is, or shall give birth to, the great man of his race, a helper, a provider for the world's hunger: so he grows jealous with his blood; the dead grandfather may have presaged the possible son; besides, it is a debt he owes to this coming Saul to tell him whence he came. There are some classes, free and slave, out of whom society has crushed this hope: they have no clan, no family-names among them, therefore. This idiot-boy, chosen by God to be anointed with the holy chrism, is only "Tom,"—"Blind Tom," they call him in all the Southern States, with a kind cadence always, being proud and fond of him; and yet—nothing but Tom? That is pitiful. Just a mushroom-growth,—unkinned, unexpected, not hoped for, for generations, owning no name to purify and honor and give away when he is dead. His mother, at work to-day in the Oliver plantations, can never comprehend why her boy is famous; this gift of God to him means nothing to her. Nothing to him, either, which is saddest of all; he is unconscious, wears his crown as an idiot might. Whose fault is that? Deeper than slavery the evil lies.
Mr. Oliver did his duty well to the boy, being an observant and thoroughly kind master. The plantation was large, heartsome, faced the sun, swarmed with little black urchins, with plenty to eat, and nothing to do.
All that Tom required, as he fattened out of baby- into boyhood, was room in which to be warm, on the grass-patch, or by the kitchen-fires, to be stupid, flabby, sleepy,—kicked and petted alternately by the other hands. He had a habit of crawling up on the porches and verandas of the mansion and squatting there in the sun, waiting for a kind word or touch from those who went in and out. He seldom failed to receive it. Southerners know nothing of the physical shiver of aversion with which even the Abolitionists of the North touch the negro: so Tom, through his very helplessness, came to be a sort of pet in the family, a playmate, occasionally, of Mr. Oliver's own infant children. The boy, creeping about day after day in the hot light, was as repugnant an object as the lizards in the neighboring swamp, and promised to be of as little use to his master. He was of the lowest negro type, from which only field-hands can be made,—coal-black, with protruding heels, the ape-jaw, blubber-lips constantly open, the sightless eyes closed, and the head thrown far back on the shoulders, lying on the back, in fact, a habit which he still retains, and which adds to the imbecile character of the face. Until he was seven years of age, Tom was regarded on the plantation as an idiot, not unjustly; for at the present time his judgment and reason rank but as those of a child four years old. He showed a dog-like affection for some members of the household,—a son of Mr. Oliver's especially,—and a keen, nervous sensitiveness to the slightest blame or praise from them,—possessed, too, a low animal irritability of temper, giving way to inarticulate yelps of passion when provoked. That is all, so far; we find no other outgrowth of intellect or soul from the boy: just the same record as that of thousands of imbecile negro-children. Generations of heathendom and slavery have dredged the inherited brains and temperaments of such children tolerably clean of all traces of power or purity,—palsied the brain, brutalized the nature. Tom apparently fared no better than his fellows.
It was not until 1857 that those phenomenal powers latent in the boy were suddenly developed, which stamped him the anomaly he is to-day.
One night, sometime in the summer of that year, Mr. Oliver's family were wakened by the sound of music in the drawing-room: not only the simple airs, but the most difficult exercises usually played by his daughters, were repeated again and again, the touch of the musician being timid, but singularly true and delicate. Going down, they found Tom, who had been left asleep in the hall, seated at the piano in an ecstasy of delight, breaking out at the end of each successful fugue into shouts of laughter, kicking his heels and clapping his hands. This was the first time he had touched the piano.
Naturally, Tom became a nine-days' wonder on the plantation. He was brought in as an after-dinner's amusement; visitors asked for him as the show of the place. There was hardly a conception, however, in the minds of those who heard him, of how deep the cause for wonder lay. The planters' wives and daughters of the neighborhood were not people who would be apt to comprehend music as a science, or to use it as a language; they only saw in the little negro, therefore, a remarkable facility for repeating the airs they drummed on their pianos,—in a different manner from theirs, it is true,—which bewildered them. They noticed, too, that, however the child's fingers fell on the keys, cadences followed, broken, wandering, yet of startling beauty and pathos. The house-servants, looking in through the open doors at the little black figure perched up before the instrument, while unknown, wild harmony drifted through the evening air, had a better conception of him. He was possessed; some ghost spoke through him: which is a fair enough definition of genius for a Georgian slave to offer.
Mr. Oliver, as we said, was indulgent. Tom was allowed to have constant access to the piano; in truth, he could not live without it; when deprived of music now, actual physical debility followed: the gnawing Something had found its food at last. No attempt was made, however, to give him any scientific musical teaching; nor—I wish it distinctly borne in mind—has he ever at any time received such instruction.
The planter began to wonder what kind of a creature this was which he had bought, flesh and soul. In what part of the unsightly baby-carcass had been stowed away these old airs, forgotten by every one else, and some of them never heard by the child but once, but which he now reproduced, every note intact, and with whatever quirk or quiddity of style belonged to the person who originally had sung or played them? Stranger still the harmonies which he had never heard, had learned from no man. The sluggish breath of the old house, being enchanted, grew into quaint and delicate whims of music, never the same, changing every day. Never glad: uncertain, sad minors always, vexing the content of the hearer,—one inarticulate, unanswered question of pain in all, making them one. Even the vulgarest listener was troubled, hardly knowing why,—how sorry Tom's music was!
At last the time came when the door was to be opened, when some listener, not vulgar, recognizing the child as God made him, induced his master to remove him from the plantation. Something ought to be done for him; the world ought not to be cheated of this pleasure; besides—the money that could be made! So Mr. Oliver, with a kindly feeling for Tom, proud, too, of this agreeable monster which his plantation had grown, and sensible that it was a more fruitful source of revenue than tobacco-fields, set out with the boy, literally to seek their fortune.
The first exhibition of him was given, I think, in Savannah, Georgia; thence he was taken to Charleston, Richmond, to all the principal cities and towns in the Southern States.
This was in 1858. From that time until the present Tom has lived constantly an open life, petted, feted, his real talent befogged by exaggeration, and so pampered and coddled that one might suppose the only purpose was to corrupt and wear it out. For these reasons this statement is purposely guarded, restricted to plain, known facts.
No sooner had Tom been brought before the public than the pretensions put forward by his master commanded the scrutiny of both scientific and musical skeptics. His capacities were subjected to rigorous tests. Fortunately for the boy: for, so tried,—harshly, it is true, yet skilfully,—they not only bore the trial, but acknowledged the touch as skilful; every day new powers were developed, until he reached his limit, beyond which it is not probable he will ever pass. That limit, however, establishes him as an anomaly in musical science.
Physically, and in animal temperament, this negro ranks next to the lowest Guinea type: with strong appetites and gross bodily health, except in one particular, which will be mentioned hereafter. In the every-day apparent intellect, in reason or judgment, he is but one degree above an idiot,—incapable of comprehending the simplest conversation on ordinary topics, amused or enraged with trifles such as would affect a child of three years old. On the other side, his affections are alive, even vehement, delicate in their instinct as a dog's or an infant's; he will detect the step of any one dear to him in a crowd, and burst into tears, if not kindly spoken to.
His memory is so accurate that he can repeat, without the loss of a syllable, a discourse of fifteen minutes in length, of which he does not understand a word. Songs, too, in French or German, after a single hearing, he renders not only literally in words, but in notes, style, and expression. His voice, however, is discordant, and of small compass.
In music, this boy of twelve years, born blind, utterly ignorant of a note, ignorant of every phase of so-called musical science, interprets severely classical composers with a clearness of conception in which he excels, and a skill in mechanism equal to that of our second-rate artists. His concerts usually include any themes selected by the audience from the higher grades of Italian or German opera. His comprehension of the meaning of music, as a prophetic or historical voice which few souls utter and fewer understand, is clear and vivid: he renders it thus, with whatever mastery of the mere material part he may possess, fingering, dramatic effects, etc.: these are but means to him, not an end, as with most artists. One could fancy that Tom was never traitor to the intent or soul of the theme. What God or the Devil meant to say by this or that harmony, what the soul of one man cried aloud to another in it, this boy knows, and is to that a faithful witness. His deaf, uninstructed soul has never been tampered with by art-critics who know the body well enough of music, but nothing of the living creature within. The world is full of these vulgar souls that palter with eternal Nature and the eternal Arts, blind to the Word who dwells among us therein. Tom, or the daemon in Tom, was not one of them.
With regard to his command of the instrument, two points have been especially noted by musicians: the unusual frequency of occurrence of tours de force in his playing, and the scientific precision of his manner of touch. For example, in a progression of augmented chords, his mode of fingering is invariably that of the schools, not that which would seem most natural to a blind child never taught to place a finger. Even when seated with his back to the piano, and made to play in that position, (a favorite feat in his concerts,) the touch is always scientifically accurate.
The peculiar power which Tom possesses, however, is one which requires no scientific knowledge of music in his audiences to appreciate. Placed at the instrument with any musician, he plays a perfect bass accompaniment to the treble of music heard for the first time as he plays. Then taking the seat vacated by the other performer, he instantly gives the entire piece, intact in brilliancy and symmetry, not a note lost or misplaced. The selections of music by which this power of Tom's was tested, two years ago, were sometimes fourteen and sixteen pages in length; on one occasion, at an exhibition at the White House, after a long concert, he was tried with two pieces,—one thirteen, the other twenty pages long, and was successful.
We know of no parallel case to this in musical history. Grimm tells us, as one of the most remarkable manifestations of Mozart's infant genius, that at the age of nine he was required to give an accompaniment to an aria which he had never heard before, and without notes. There were false accords in the first attempt, he acknowledges; but the second was pure. When the music to which Tom plays secondo is strictly classical, he sometimes balks for an instant in passages; to do otherwise would argue a creative power equal to that of the master composers; but when any chordant harmony runs through it, (on which the glowing negro soul can seize, you know,) there are no "false accords," as with the infant Mozart. I wish to draw especial attention to this power of the boy, not only because it is, so far as I know, unmatched in the development of any musical talent, but because, considered in the context of his entire intellectual structure, it involves a curious problem. The mere repetition of music heard but once, even when, as in Tom's case, it is given with such incredible fidelity, and after the lapse of years, demands only a command of mechanical skill, and an abnormal condition of the power of memory; but to play secondo to music never heard or seen implies the comprehension of the full drift of the symphony in its current,—a capacity to create, in short. Yet such attempts as Tom has made to dictate music for publication do not sustain any such inference. They are only a few light marches, gallops, etc., simple and plaintive enough, but with easily detected traces of remembered harmonies: very different from the strange, weird improvisations of every day. One would fancy that the mere attempt to bring this mysterious genius within him in bodily presence before the outer world woke, too, the idiotic nature to utter its reproachful, unable cry. Nor is this the only bar by which poor Tom's soul is put in mind of its foul bestial prison. After any too prolonged effort, such as those I have alluded to, his whole bodily frame gives way, and a complete exhaustion of the brain follows, accompanied with epileptic spasms. The trial at the White House, mentioned before, was successful, but was followed by days of illness.