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



quently Schwann, succeeded in tracing into the cells of the epidermis. The latter 

 supposes that a cell-formation takes place immediately on the surface of the cutis -f-. 

 But here I cannot help referring- to the process of division we have seen reproducing 

 the epithelium-tables of the Tadpole ; a process which it seems probable, from other 

 of my observations, is universal, including, therefore, even the epidermis. 



The Elements of Blood-vessels compared with Corpuscles of the Blood. 



130. Capillaries in the course of formation out of corpuscles having the same ap- 

 pearance as corpuscles of the blood, are represented in fig. 107- These corpuscles, 

 still red (a), apply themselves together so as to form an object resembling a neck- 

 lace composed of elliptical beads ; and having coalesced, and become pale (/3), and 

 the membranous partitions (at the extremities of the beads) liaving disappeared, they 

 constitute a tube. The membrane of this tube is formed in the same manner as, ac- 

 cording to my observations, the membrane of the ovisac, the chorion, and other 

 membranes ; — namely, by the coalescence of discs, as at a in the upper part of the 

 above figure. At certain parts, the corpuscles apply tliemselves in such a manner 

 as to form a branclied vessel. An example of this is to be found in the figure ; 

 which also shows the corpuscles, coalescing in this instance for the formation of ca- 

 pillaries, to have been of very minute size. They had the same appearance as young 

 corpuscles of the blood. At Hs a round space. This space was colourless, and 

 brilliantly pellucid. And I am by no means sure that it was not an orifice left in the 

 membrane of the tube (pars. 152, 162, 178.). 



131 . If the vessels have their origin in corpuscles of the blood, it is scarcely needful 

 to inquire from what source they derive the materials for their thickening also, and 

 for the formation of the several coats of which they become composed. It may be 

 mentioned, that some of the pale discs in fig. 142. — evidently derived from corpuscles 

 of the blood — seemed, by coalescence, to be entering into the formation of the mem- 

 brane of the vessel. But here also, as appears to be the case in every other tissue, 

 the original corpuscles (fig. 107.) no doubt contain within themselves the means of 

 perpetuation. 



132. While the investigations forming the subject of this memoir were in progress, 

 I received a letter from Dr. W. B. Carpenter, of which the following is an extract. 

 It requires no comment, except the expression of my concurrence, as furnished by the 

 foregoing observations: — "Having been just lecturing on the blood and the process 

 by which it becomes organized, I think it well to mention to you some views which 

 have occurred to my mind in reference to your observations on the conversion of 

 blood-corpuscles into tissue J. When lymph is thrown out upon an inflamed mem- 

 brane, and is in process of becoming organized, it has been long known that the 



t Schwann, I. c, p. 86. 



X Dr. Carpenter here refers to my first paper on the Corpuscles of the Blood, Philosophical Transactions, 

 1840, Part XL 



