The blood-corpuscle considered in its different phases of development in the animal series / by T. Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891.
Date:
1846
Catalogue details

Licence: Public Domain Mark

Credit: The blood-corpuscle considered in its different phases of development in the animal series / by T. Wharton Jones. 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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    Blood-corpuscles of the Medicinal Leech. 51. The blood examined was obtained by making incisions on the back or side of the animal after having carefully wiped the surface of the skin. In making these incisions care was taken not to cut into the stomach, or its csecal appendages, in order to obviate the possibility of foreign blood which might have been taken in as food, becoming mixed with the real blood of the animal itself. 52. In the first place it is worthy of remark, that whilst the corpuscles of the blood of the Earth-worm are the largest which I have yet found in any invertebrate animal, the corpuscles of the blood of the Leech are the smallest. 53. When the blood of the Leech is examined under the microscope as soon after its abstraction from the animal as possible, numerous corpuscles are seen having the appearance of very pale, shining, colourless, fusiform filaments, about awoth of an inch in length, and about ywoth °f an inch in breadth, less or more (fig. 9.), suspended in the red-coloured plasma. Very soon, however, the corpuscles are seen gradually to become shorter and somewhat broader, until at last they acquire an irregular cir- cular form (fig. 10.). 54. In this state the majority of the corpuscles appear to be composed of a nucleus surrounded by a collapsed and shrivelled cell-wall. And that this is so, is reduced to a certainty by the addition of water, which causes the cell to become distended and to acquire a circular form, whilst the outline of the cellseform nucleus appears more distinctly defined (figs. 11 and 12.). 55. Thus distended, the cell is from 3Woth to 3-gVoth of an inch in diameter, and the nucleus yrrooth, or more. 56. Many of the cells transmit the light slightly tinged red, as if there was some colouring matter lining their interior (fig. 12.). 57. The corpuscles of the blood of the Leech now described, it will have been observed, are nucleated cells. 58. Granule-cells.—Corpuscles in the blood of the Leech referrible to this head are few in number. Examples of them are delineated in figs. 7 and 8*. * I subjoin here a description of the corpuscles of the blood vomited by leeches which have never been used. This blood I found to be composed of a coloured plasma, and numerous corpuscles having a considerable resemblance to those of the blood of the animal itself after having lost their original fusiform shape, and become somewhat distended by water. On the whole, however, the corpuscles of the blood in question were somewhat larger, and appeared perhaps better defined than those of the Leech itself, especially the granule-cells, which were also more numerous, though still not so numerous as the nucleated cells. Of the granule-cell there were both coarsely and finely granular stages (figs. 13 and 14.). There were cells in transition from the granule to the nucleated phase (fig. 15.). The nucleated cells (figs. 16,17 and 18.) were most of them circular, but some were oval. Most appeared tinged red in their interior, those which did not had their cell-wall so very pale that it was apt to be overlooked. The blood contained in the-stomach of leeches which have not been used, and of which I have now briefly described the corpuscles, from what animal is it derived ? The resemblance of the blood to that of the animal itself suggests the probability that medicinal leeches suck the blood of some other kind of leech. That they suck each other’s blood has been positively denied by Dr. Rawlins Johnson. MDCCCXLVI. O