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“ Natura infinita est, sed qui symbola animadverterit
Dayk Son I ish" to the Queen.
R. Owendel JErxleben, on Stone,
THE SUCCESSIVE PRODUCTION OF
A SINGLE OVUM.
INTRODUCTORY TO THE HUNTERIAN LECTURES ON
FOR THE YEAR 1849,
DELIVERED AT THE
ROYAL COLLEGE OF SURGEONS OF ENGLAND.
RICHARD OWEN, F.R.S. &c.,
HUNTERIAN PROFESSOR AND CONSERVATOR OF THE MUSEUM.
JOHN VAN VOORST, PATERNOSTER ROW.
By the same Author.
ON THE ARCHETYPE AND HOMOLOGIES OF THE VER
TEBRATE SKELETON. 8vo. 1848.
ON THE NATURE OF LIMBS. 8vo. 1849.
Three Plates and Eleven Woodcuts. Price 6s.
THERE is a natural and irrepressible tendency in the human mind to penetrate the mystery of the beginning of things, and above all that of the origin of living things, involving our own origin.
But it is plainly denied to finite understandings to ascend to the very beginning, and to comprehend the nature of the operation of the First Cause of anything.
And perhaps the best argument from reason for a future state and the continued existence of our thinking part, is afforded by the fact of our being able to conceive the possibility of the enjoyment of such knowledge, and the consequent yearning to possess it,--that pávtevua ti of Plato, or parturient vaticination of some higher knowledge which cannot be fulfilled in the present state of our existence.
The ablest endeavours here to penetrate to the beginning of things do but carry us, when most successful, a few steps nearer that beginning, and then leave us on the verge of a boundless ocean of the unknown truth, dividing the secondary or subordinate phænomena in the chain of causation from the great First Cause.
The brief record of creation in the Sacred volume leaves us to infer that certain plastic and spermatic qualities of
common matter were operative in the production of the first organized Beings of this planet. “The earth brought forth grass and herb yielding seed after his kind, and the tree yielding fruit whose seed is in itself.” “ The waters brought forth abundantly the moving creature that hath life;" and “ the earth brought forth the living creature after his kind, cattle, and creeping thing, and beast of the earth.” But of our own species it is written, 66 God created man after his own image, in the image of God created he him ; male and female created he them.” And “God said unto them, Be fruitful, and multiply and replenish the earth.” (Gen. i. 27 and 28.)
Since that first fiat went forth, the propagation of the species of plants, animals and mankind has been left to the operation of certain natural secondary causes, which we sum up as the act of generation.'
Botanists and physiologists have observed and progressively analysed the phænomena until they have reduced them to a great degree of simplicity, the essential conditions being the same, or closely similar, in both realms of organic nature.
With regard to the animal kingdom, the generation of which here concerns us, the essential conditions of the act appear to be a nucleated cell, and the product of a nucleated cell, with the combination of the two: the nucleated cell is the 'germinal vesicle, and is the essential part of the ovum; the other nucleated cell is the sperm-cell,' and its product is the spermatozoon.
It is essential to the development of the germ that the ovum receive the matter of the spermatozoon: it is then said to be impregnated.
The phænomena that thence ensue are essentially the same up to a certain point in all animals, and consist in the formation of a germ-cell (Pl. I. fig. 4, c), and its propagation of a numerous offspring (fig. 10) at the cost of the germ-yelk (fig. 4, a), by a series of reiterated spontaneous