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



explanation of the Plates ; with the mode of origin of the pigment in the choroid. 

 The discs of the bright red ^ and g, in this figure, undergo division, and are given off, 

 to enter into the formation of the darker and blackish ^. It appears that what is 

 seen of Z, in the figure, had been formed by portions previously given off in this 

 manner. So that here, in the pigment of the eye also, we find centres (^. g.) for the 

 origin of new substance). It is important to add, that all the objects now mentioned, 

 had the appearance of altered corpuscles of the blood. 



121. The black substance found in mucus from the air-passages, arises in a 

 manner somewhat similar ; presenting itself at the outer part of corpuscles quite as 

 red as corpuscles of the blood. See fig. 72. 



122. Portions of ciliary processes, as seen in the eye of a Tadpole of 5 J'", are re- 

 presented in fig. 101. They are in outline only; for the parts composing them, from 

 their colour, form, size, and general appearance, so much resembled slightly altered 

 blood-corpuscles, that it did not appear requisite to make elaborate drawings of them. 

 It is, besides, extremely easy to repeat, and therefore to confirm, this observation, or 

 show it to have been erroneous. 



The Primitive Discs exhibit an inherent contractile power. 



123. This was manifested by the elongated discs of the epithelium-cylinder fig. 98. a, 

 /d; and by the isolated disc, two appearances of which are represented at I in the 

 same figure. This isolated disc was observed for a considerable time to change its 

 form and place. Some of the discs composing the paler part of the cylinder a, (3, 

 were, for about twenty minutes, seen to be in motion ; and there was thus produced 

 a very slow revolution of the entire object on its axis, in the direction of the arrow. 

 (In connection with this subject, it may be mentioned, that the object in fig. 139 

 which is more finished in delineation than the rest, and constituted the centre of the 

 forming crystalline, on being viewed repeatedly for a considerable time, was found to 

 vary in its appearance ; a phenomenon which seemed to arise from the discs changing 

 their position. This object, as will be found stated elsewhere (par. 181.), had all the 

 redness of a corpuscle of the blood.) 



The Nuclei of Blood-corpuscles furnish themselves with Cilia, revolve, and perform 



Locomotion. 



124. Ciliated corpuscles are seen in figs. 105 and 104. Those in the first of these 

 two figures were observed in the blood of a rabbit, taken from vessels in the imme- 

 diate neighbourhood of a Graafian vesicle, which, from its size and vascularity, had 

 evidently been destined to expel an ovum. The corpuscles in the latter figure were 

 noticed in a substance from the eye of a foetal calf of b\ inches, more particularly 

 described in the explanation of the Plates. The rabbit had been killed eighteen 



