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



154. Here also, corpuscles having the same appearance as young corpuscles of the 

 blood, become orange-shaped, present two or more bright points with red colouring 

 matter between them (see the figures) ; and, as the colouring matter disappears, 

 admit of being traced into the masses of discs just mentioned ; these being the altered 

 nuclei of the corpuscles in question. We thus find in the elements of the retina, as 

 well as in those of cellular tissue (par. 134.), the same appearances as those presented 

 in the formation of pus-globules out of corpuscles of the blood. 



155. After the corpuscle, having the same appearance as corpuscles of the blood, 

 has become a mass of discs, the discs may undergo division and subdivision to an 

 inconceivable extent, and to which we can set no bounds, as regards either the 

 number or the minuteness of the resulting objects. It will be observed, from fig. 130, 

 that cells are formed ; their membranes arising — as elsewhere, according to my ob- 

 servations — from the coalescence of minute discs. These cells will be found minutely 

 described in the explanation separately given. It is not my purpose in this memoir 

 to follow their subsequent progress. 



156. I have frequently met with the rudiment of the spinal chord, — sometimes in 

 fragments, sometimes almost entire, — as it exists in the tail of the Tadpole ; this 

 larva measuring 5'" or 5 J'". Its newest part I found composed entirely of corpuscles 

 having essentially the same appearance as corpuscles of the blood, and being in a 

 state resembling (but somewhat more advanced than) that which they presented in 

 the optic nerve fig. 124 a, and also arranged in lines. In fig. 132. is an outline of 

 some of the corpuscles which I observed constituting this structure in a Tadpole of 

 5 J'". The spinal chord has uniformly appeared to be less advanced than the cellular 

 tissue which seemed to be entering into the formation of its sheath (par. 136.). 



157. Corpuscles from the cortical substance of the brain in a foetal Calf of 5^ 

 inches, are seen in fig. 133: and fig. 134. represents some of those observed in the 

 medullary part of this organ, in the same subject. 



158. Objects such as those in the first of these two figures, were observed in large 

 number ; and often seen to be flattish in their form. They were all more or less 

 red, — some blood-red ; all were either discs, or composed of discs, — being either 

 themselves corpuscles, having the same appearance as corpuscles of the blood, or 

 immediately derived from such corpuscles. Here, as often observed in other parts 

 in the course of formation, the corpuscles were found to be of a minute size ; being 

 apparently young corpuscles. They presented the same gradual transition into the 

 elements of the brain, as we have seen in other parts, regarding a change in form, 

 colour, and division into discs ; besides the previous appearance of an orifice {(B), in 

 the situation of the depression presented by the corpuscle when discoid in its form. 

 The gradual formation of a membrane too, by coalescence of the outer discs, was 

 witnessed here (;j). These details will be found more fully given in the explanation 

 of the Plates. And perhaps there is no figure more instructive, as regards the changes 



