48 Transactions of the 



escaped, the movement of the corpuscles naturally ceased. To this 

 circumstance it may be ascribed, too, that in a second piece, which 

 I also removed with the scissors, the movement only slowly took 

 place, and lasted but a short time ; for, at this time, the canals of 

 the entire wall of the vesicle, as well as those of the small piece 

 removed, had lost a part of their blood corpuscles through the 

 orifices caused by the section. There was a difference in the 

 diameters of the canals ; for, while some were not larger than a 

 capillary vessel, others had attained a diameter double or three 

 times greater. In some of the larger ones, the blood corpuscles 

 were so densely crowded that they assumed, by mutual pressure, a 

 temporarily hexagonal form. Besides those blood corpuscles, con- 

 tained in the canals, a great number of others were observed, 

 ^'hich, accumulated without any special arrangement in round or 

 oblong masses, were also in motion. It was these accumulations 

 that caused the above-mentioned red spots upon the outer surface 

 of the vesicle. A considerable portion of these blood corpuscles 

 remained in their places after the evacuation of the canals. The 

 real tissue of the vesicle was composed of very large and clear 

 hexagonal cells, containing a large round nucleus. These proved 

 to be, as we shall hereafter see, the primary organs of origin of the 

 coloured blood corpuscles. Before we can proceed, however, to give 

 a special description of these cells, as well as of their arrangement, 

 it will first be necessary to examine a little closer the embryonic 

 blood corpuscles themselves. 



Those bodies, which escaped through the cut orifices of the canals 

 (Fig. 2), corresponded in general to the fully-developed coloured 

 blood corpuscles of man or other mammalia; they only differed 

 from each other in size. They were of the usual yellowish tint, 

 entirely homogeneous in composition, soft, elastic, and round. No 

 trace of the existence of a membrane could be discovered in their fresh 

 and imchanged condition. The greater portion of them were of the 

 size of the fully-developed human corpuscles, and differed from these 

 in no way, excepting that the central depression was either wanting 

 or but slightly marked. The whole corpuscle resembled rather a 

 flattened disk with a rounded margin. Another portion, embracing 

 the larger specimens, consisted of breeding or mother corpuscles, 

 the several diameters of which ranged from -^^o to ^IJ^o mm., or even 

 more. These bodies contained within their substance embryo-blood 

 corpuscles, and many of them furthermore distinguished themselves 

 from other blood corpuscles by certain regularly-formed concave 

 depressions on their surface, corresponding to the segment of a 

 sphere, and indicating the place where the young corpuscle had 

 been detached from the mother-body (Fig. 2). AVhile the larger 

 of these mother-bodies contained from three to four embryo-cor- 

 puscles, the smaller ones usually contained but one. 



