DR. MARTIN BARRY ON THE CORPUSCLES OF THE BLOOD. 
601 
present paper. And I confirm the statements made on that occasion; namely, that 
the cells send out processes or arms which interlace ; that the contained pellucid 
object seems to enter into the processes or arms ; that it is by a coalescence of the 
cells that the incipient chorion is formed ; that the additions of cells appear to be 
continued up to the period when villi are produced ; and that the villi themselves 
are probably formed out of the same kind of cells. It remains to add, that the cells 
in question, delineated in that paper, not merely have the same appearance, but are 
identical with those in Plate XXIX. fig - . 7- of the present memoir: in other words, 
that the chorion is formed of cells which are altered corpuscles of the blood. 
25. In Plate XXIX. fig. 8. are seen some of the very earliest traces of the formation 
of the chorion. The cells (g 1 ) of the tunica granulosa were described on a former 
occasion'|~, as becoming club-shaped and connected with the membrane f by their 
pointed extremities alone, after the fecundation of the ovum. Such is the form and 
position of the cells g 1 exhibited, for the most part in outline, in this figure. One 
purpose answered by the changes just mentioned as presented by the cells g 1 , seems 
to be that blood-corpuscles ( cho .) find their way between them, and have space for 
applying themselves to the membrane f while this membrane continues to be pro- 
tected by those cells;};. In fig. 8. several blood-corpuscles (cho.) are seen to have 
occupied the latter situation, where, in some instances, they appear to effect the alter- 
ations in their form above described §. Three of them, it will be observed, had become 
cells, and two were in the same stage as some of those in fig. 7, having begun to send 
out processes or arms||. 
26. For the announcement that the chorion is formed by corpuscles of the Blood, 
physiologists, I apprehend, are not prepared ; it being the generally received opinion 
that the formation and the nourishment of organs are effected through its fluid part^[. 
But the next section records facts which, if established by future observation, involve 
more important consequences. 
Muscular Fibre formed of Cells derived from Corpuscles of the Blood. 
2 7- The latest researches, which have been published, on the mode of origin of 
muscle, are I believe those of Valentin and Schwann. 
t “ Third Series,” l. c., par. 345. 
+ Which also may afford fluid for the imbibition of the chorion. The protection above referred to is 
possibly essential during the transit of the ovum into the Fallopian tube. 
§ In other instances those alterations occur before the blood-corpuscles take their places on the ovum. 
|| In Insects, a structure supposed to be analogous to the chorion of Mammalia, is often found to present 
itself in the ovary, and it “ not rarely exhibits an elegant delineation consisting of flat coalesced cells.” 
(R. Wagner, A. Encycl. d. W. u. K. Erste Section, XXXII. “ Ei,” p. 4.) 
An eminent physiologist, however, has recently remarked : “ What becomes of the blood-corpuscles, — 
whether they are transformed, — whether entirely or in part they are here and there deposited, — whether they 
dissolve, &c. has not been ascertained ; we are reduced to mere hypotheses.” (R. Wagner, Beitriige zur 
vergl. Phys. H. II. S. 54. . 
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