On the corpuscles of the blood / by Martin Barry. Pts. [I]-III.

  • Martin Barry
Date:
1840-1841
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Licence: Public Domain Mark

Credit: On the corpuscles of the blood / by Martin Barry. Pts. [I]-III. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    be distinguished, either in colour, form, or general appearance. (The epithelium- cells in question are frequently observed to lie in the same direction, their long axes being parallel.) 50. But if the great mass of the soft parts, muscle, is formed of corpuscles of the blood, how many tissues are there which they may not form?-f~ 51. We are indebted to Schwann for the very important discovery, that “for all the elementary parts of organisms there is a common principle of developmentthe elementary parts of tissues having, as he has shown, alike origin in cells, however dif- ferent the functions of those tissues. The facts made known in the present memoir, if established by future observation, will not only afford proofs of the justness of the views of Schwann, but they will farther show that objects having all the same colour, form, and general appearance, namely, the corpuscles of the blood, enter immediately into the formation of tissues which physiologically are extremely different. We have seen some of these corpuscles to arrange themselves into muscular fibre, and others to become metamorphosed into constituent parts of the chorion. It is not, however, more difficult to conceive objects so much alike undergoing transformations for pur- poses so different, than it is to admit a fact made known by two of my preceding memoirs;};; namely, that the nucleus of a cell having a central situation in the group which constitutes the germ, is developed into the whole embryo, while the nuclei of cells occupying less central situations in the group, form no more than a minute por- tion of a membrane§. It is known that in the bee-hive, a grub is taken for a special purpose, from among those born as workers, which it perfectly resembles until nou- rished with peculiar food, when its development takes a different course from that of every other individual in the hive. f “ The nerves,” says Schwann, “ appear to arise in the same manner as the muscles; namely, through coalescence of primary cells in contact with one another and in a line, by which there is formed a secondary cell. But the primary nerve-cells have not been with certainty observed, because—so long as they are primary cells—they are not to be distinguished from the neutral cells, out of which arises the whole organ.***The fibres [secondary cells] are pale, granulated, and***hollow. There now takes place, as in muscles, a secondary de- posit upon the inner surface of the fibre-wall, that is, upon the inner surface of the membrane of the secondary nerve-cell.***On the appearance of this deposit the cell-nuclei are usually absorbed; yet single ones continue, and then lie externally between the [deposited] substance and the [secondary] cell-membrane,***as in muscles. The remaining cavity of the secondary cell appears to be occupied by a tolerably firm substance, the band dis- covered by Remak.” (Schwann in R. Wagner’s Lehrbuch der Physiologie, I. pp. 141, 142.) Should it be found that nerves too are formed of blood-corpuscles, this band of Remak may perhaps be constituted by coa- lesced objects similar to those apparently uniting to form the central substance in the muscle-cylinder (par. 38.), and which appear to be the essential part of altered corpuscles of the blood.—“ The external appearance of tendons in the embryo,” says Valentin, “ is reddish, and not unlike the pale muscle-structures.” (Entwickel- ungsgeschichte, p. 270.) X Researches in Embryology, Second and Third Series, l. c. § Which I provisionally called the amnion.