204 Dr Martin Barry on the 



be "cast off as a useless member" and " absorbed," is the 

 seat of a most elaborate process, which I will now endeavour 

 to describe : first remarking, that the woodcuts are intended 

 for the purpose of assisting in the description of that process, 

 rather than as minutely representing nature. Drawings in 

 which the latter has been attempted, taken from hundreds in 

 my memoirs, are given in the plates ; and these will be ren" 

 dered more intelligible by the woodcuts. (In many of the draw- 

 ings, for instance in those of fig. 39, Plate I., the structure 

 is so minute that it should be viewed with a pocket lens.) 



The " cytoblast" of Schleiden has usually a discoid or 

 amygdaloidal form, and in substance appears finely granular* 

 (fig. 4) ; and his " nucleolus,*" the pellucid point in fig. 4, I 

 find to represent the situation of a brilliantly pellucid sub- 

 stance, which, from its appearance, I have called kyaline.\ 



Fig. 2. Two portions of hyaline enlarged, and surrounded 

 by globules of extreme minuteness, which seem Fig. 2. 

 to have their orio-in in the bodies they sur- 

 round. One of these bodies presents a faint I oo "Jo % 



Og O Q O 



circular marking at the side, not yet formed in 

 the other. This circular marking is the incipient nucleolus. 

 Compare with a and /3, the two states of nuclei, in Fig. 33^ 

 Plate I. ; a nucleolus being there present in /3, and not yet 

 formed in a. 



Fig. 3. That which was a large portion of hyaline in 

 fig. 2, is now an incipient cytoblast, and already ^ 3 

 membranous at the surface ; the minute globules, 

 now no longer seen, having apparently entered into (CTx 

 the formation of its membrane. Compare with V_y 

 many figures in Plate I. 



Fig. 4. The cytoblast of Schleiden ; differing from the 

 body fig. 3, in being finely granular, except in the j,. ^ 

 region of the circular marking or nucleolus, which 

 first made its appearance in one of the portions of ^^ 

 hyaline fig. 2. Compare with figs. 35, 36, &c., ^0 

 Plate I. 



* In animals this finely granular substance is, or corresponds to, the red 

 colouring matter of the corpuscles of the blood. See figs. 35, 36, &c., in Plate I. 

 t A terra suggested to me by Professor Owen. 



