in which the separation in question had been observed), the effect of acetic acid, used in the examination, — but that such separation i& natural, apparently common to nuclei in general, and forming part of the process by which cells are reproduced. The author had far- ther shown the so-called nucleolus to be not a distinct object ex- isting before the nucleus, but merely one of a series of appearances arising in succession, the one within the other, at a certain part of the nucleus, and continuing to arise even after the formation of the cell. These views he now confirms ; and in the present paper shows that they admit of being extended to the corpuscles of the blood.
He then compares appearances observed in the latter with those he had traced in the ovum. These relate to the number of parts of which the nucleus is at different periods composed, — the nature of the nucleolus, — the communication between the nucleolus and the exterior of the cell, — the formation of the contents of the cell out of the nucleus, — the final division of the nucleus into the foundations of a limited number of young cells, destined to succeed the parent cell, — and the escape of the young cells for this purpose. It follows from these investigations, that the corpuscles of the blood are gene- rated by a process essentially the same as that giving origin to those cells which are the immediate successors of the germinal vesicle, or original parent cell ; it being also by a continuation of the same process that the coi-puscle of the blood divides itself into the minuter objects figured by the author in his former paper on the blood.
He adds, that in its form and internal state, the blood-corpuscle found in the adult of certain animals, very much resembles that ex- isting only in the fcetal life of others. It is incidentally remarked, that the fcetal brain, at certain periods, appears to consist almost entirely of objects very much resembling those which, in some stages, form the nuclei in the foetal corpuscles of the blood.
The author concludes, by expressing his opinion, that the mode of evolution of the minute mammiferous ovum is deserving of close attention, in connexion with some of the processes by which nourish- ment is communicated, and the growth of the body effected, at aE future periods of life.
January 21, 1841.
Sir JOHN BARROW, Bart., V.P., in the Chair.
Peyton Blackiston, M.A. & M.D., Captain Henry Rowland Brand- reth, R.E., and Joseph Edye, Esq., were balloted for and duly elected into the Society.
A paper was in part read, entitled, " On the action of certain Inorganic Compounds, when introduced directly into the Blood." Bv J. Blake, Esq., M.R.C.S. Communicated by P. M. Roget, M.D., Sec. R.S.
