DR. MARTIN BARRY ON THE CORPUSCLES OF THE BLOOD. 203 



substance is required to produce the separation in question ; this separation being 

 natural, apparently common to nuclei in general, and forming part of the process by 

 which cells are reproduced. We found that young cells originate through division 

 of the nucleus of the parent cell, instead of arising as a sort of " product of crys- 

 tallization, in the fluid cytoblastema" of the parent cell, as since supposed by 

 REicHERT-f". The so-called nucleolus had been described as a distinct object, exist- 

 ing before the nucleus. But, we saw the nucleolus to be merely one of a series of 

 appearances arising in succession, the one within the other, at a certain part of the 

 periphery of the nucleus ; and continuing to arise even after the formation of the cell. 



55. My later investigations, I have now the satisfaction of stating, confirm the 

 opinions just referred to, as well as others which I formerly expressed, but which are 

 not recapitulated here ; and the object of the present paper is to show, that they 

 admit of being extended to the corpuscles of the blood J. 



56. The observations recorded in this memoir are based on an examination of the 

 blood in all classes of vertebrated animals, in the embryo of Mammalia as well as 

 that of Birds, and in some of the Invertebrata. 



57. In certain states of the corpuscle of the blood its nucleus is single, like the 

 central portion of the germinal spot in the germinal vesicle of the ovum. Such is 

 the case at a in Plate XVIII. fig. 51. and at f] in fig. 54. from Fishes, at a in figs. 49 

 and 50. from two of the Reptilia, at (B in figs. 43 and 45. from the Bird, and in fig. 32. 

 from the Mammal. In all the blood-corpuscles now referred to — which it will be 

 seen are those of the four classes of vertebrated animals, including the two divisions 

 of both Reptiles and Fishes, — the nucleus has a cavity or a depression ; at the margin 

 of which there occurs a high refraction of light. The appearance thus produced, 

 seems to represent one of the states of the " nucleolus" of authors, in other cells. 



58. The centre of the germinal spot undoubtedly communicates at a certain period 

 with the exterior of the germinal vesicle ; for strong presumptive evidence was 

 brought forward, showing the introduction of some substance into the centre of this 

 spot from the exterior of its vesicle. And, besides, 1 mentioned that in a certain 



t Das Entwickelungsleben im Wirbelthier-reidi, 1840, p. 2. 



I They probably admit of being extended much farther. I cannot, indeed, but recognize in a paper by Pro- 

 fessor V ALENTiN, not merely dissent (in some instances at least) from the view above referred to, — that the 

 nucleus is cast ofl' as " useless," — but also facts which go to corroborate some of my own observations ; how- 

 ever little the conclusions at which I arrived, resemble those of the author now mentioned. See Mijilbb's 

 Archiv, 1840, Heft II. pp. 229, 230, and 235. The recent work of Reichert also, before referred to, contains 

 observations respecting which I would make the same remark. This author, however, adopts the mistaken 

 view, that the nucleus of the cell is absorbed. For, considering the germinal vesicle as a nucleus, he therefore 

 supposes it to disappear (/. c, pp. 102, 103). The " finely granular" and " globular precipitate" of Reichert, 

 appearing around the nucleus, evidently arose from decomposition of the free portion of the nucleus (See my 

 Third Series, I. c, par. 391)^ to which cause seems referable the reduction lie observed in the size of this 

 object (/. c, p. 91)» 



MDCCCXLI. 2 E 



