CELLULAR ELEMENTS OF THE GROUND-SUBSTANCE. 15 



great extent, resembles a group of endothelial plates branching out- 

 wards. We shall return to these structures afterwards, in the chapter 

 on lymphatic vessels. 1 



Besides the above-mentioned small young patches, we find patches 

 of the following various structure : a smaller or greater number of 

 capillary blood-vessels are imbedded in a matrix, which contains 

 besides a limited number of spherical lymphoid cells of different 

 sizes, branched cells, lying more or less closely by each other ; in 

 some places, the matrix appears to be completely supplanted by these 

 latter ones. Where they are not crowded together it is distinctly to 

 be seen that they are provided with processes which join each other 

 and those of the neighbouring cells. In the intermediate portions 

 between the latter and the former the cells become less branched, 

 their processes much shorter. 



On negative silver-stained preparations, viz. in which the lymph- 

 canalicular system has remained clear, the lacunae of those cells 

 appear to be separated from each other merely by lines in those 

 places where the cells lie crowded together. From the fact that in 

 positive silver-stained preparations the cells of the intermediate 

 portions possess, instead of the single ovoid clear nucleus, a con- 

 stricted or even a completely divided nucleus, and secondly, that the 

 cell bodies themselves exhibit sometimes furrows like marks of 



1 As the reader may have already observed, I have, as regards the cellular elements 

 of the omentum, quite the same opinion as Rollett has of those of the cornea. In both 

 cases the branched cells are more or less flattened parallel to the surface, and in both 

 cases the lymph-canalicular system corresponds to those cells. In the omentum, as well 

 as in the cornea, the migratory cells are always found in the lymph-canalicular system, 

 and, as we shall see afterwards, in the cedematous omentum the lacunae and canaiiculi 

 may .be distended by serous fluid and lymphoid corpuscles, which find their way through 

 the lymph-canalicular system to the lymphatic vessels. Rollett has treated in his paper 

 the branched corpuscles of the cornea and their lymph-canalicular system in such an 

 exhaustive manner that it is hardly necessary to enter again into a controversy about the 

 nature of the connective tissue corpuscles and the lymph-canalicular system of Reckling- 

 hausen. As regards the serous membranes, there cannot be the slightest doubt about the 

 cellular elements of the ground-substance being more or less flattened branched-nucleated 

 protoplasmic cells, and the lymph-canalicular system representing merely the spaces in 

 the ground-substance for those cells ; and I cannot agree by any means with the assertion 

 of Schweigger-Seidel and Boll that the connective tissue corpuscles in general represent 

 elastic plates which play only a passive part. We shall see afterwards that the proto- 

 plasmic nature of the connective tissue cells of the serous membranes plays an important 

 part in the normal condition, and still more in chronic inflammation. 



