Royal Microscopical Society. 51 



prived me of the opportunity of studying the details of that system 

 of canals somewhat closer, it, nevertheless, enabled me better to 

 understand the true signification of those large hexagonal cells, 

 I discovered, namely, that those accumulations of blood corpuscles 

 were situated between two membrane-like layers of these cells, 

 and that I had in reality before me a system of pri^nary glandular 

 follicles (see Fig. 3). The latter themselves were very irregular 

 in size and form, and appeared somewhat flatly pressed, which, 

 however, may be ascribed to the emptying of their blood corpuscles, 

 as well as to the dehcacy of the tissue yielding to the weight of 

 the covering glass. On examination with an amplification of 65 

 diameters, the whole appeared as a close group of islands, among 

 which the canals could be seen in the form of clear stripes passing 

 between the opaque follicles (Fig. 5). A higher amplification 

 showed that the principal elements of the latter, the large cells, 

 distinguished themselves by a more or less hexagonal form, as well 

 as by a fine, sharply-defined, double contour, and contained, besides 

 a large round double-contoured nucleus, also a number of smaller 

 ones. These latter were pale bodies, also bordered by a double 

 contour, and represented, as we shall see below, the successive 

 stages of the large nucleus. Two to three of these small nuclei 

 were also observed in the interior of the large and fully-developed 

 nuclei. Some of the cells even contained two of these latter, one 

 of which, however, was always smaller than the other. The proto- 

 plasm filling up the interior of the cells was finely granular. I'he 

 diameter of the cells ranged from ^VV to -i-^o mm. ; that of the large 

 mother-nuclei from s%o to ^^o nim. The small free nuclei con- 

 tained within the cells measured from -e^o to g^o mm., while the 

 diameter of those contained within the large nuclei never exceeded 

 ^^0- mm. The walls of the canals occupying the interspaces of the 

 follicles consisted of a fine fibrous tissue, which, in the form of an 

 exceedingly delicate membrane, extended itself over the former to 

 perform the function of a supporting tissue (see Fig. 3 and ex- 

 planation). 



In considering the construction of these large hexagonal cells, as 

 well as their arrangement in the form of a foUicle, a little closer, we 

 shall find that a certain relationship between the nuclei contained 

 within them, and those large, above described, mother blood cor- 

 puscles, cannot be overlooked. On the contrary, those pale, double- 

 contoured bodies within the cells, seem to represent the successive 

 stages of development of the larger mother- nuclei, while these latter 

 are most hkely identical with the breeding or mother corpuscles. 

 The only difierence which could possibly be discovered would con- 

 sist in the presence of a double contour, and in the want of colour 

 in the nuclei contained within the cells. But as the double contour 

 itself already indicates the existence of an enveloping membrane, 



