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 £ 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 (h. s.) 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|"', 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, 
(3 ; and by the isolated disc, two appearances of which are represented at & 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 inches, more particularly 
described in the explanation of the Plates. The rabbit had been killed eighteen 
