314 THE LYMPHATIC SYSTEM, BY F. v. RECKLINGHAUSEN". 



form of the cells ; in other words, that the solid substance 

 presents cavities which precisely correspond to the cells and 

 their processes. In the meanwhile, if we allow the corpuscles 

 of the cornea, with all their processes, to come into strong relief, 

 by exposure for several hours in the moist chamber (which is 

 the best method of rendering them distinct), the ramifications 

 of their processes are always found to be few in number, and 

 the communications between their finest branches to be dis- 

 covered only with difficulty, whilst the silvered lines form a close 

 plexus ; the stellate corpuscles of the cornea, however, do not be- 

 come covered with the tracings. But further, we see the actively 

 moving cells of the cornea traverse its substance in all direc- 

 tions, without, as a rule, attaching themselves to the processes 

 of the stellate, immovable corneal corpuscles, though they 

 sometimes do so with great distinctness; with the spaces in 

 which the latter lie, channels must therefore still be in com- 

 munication, which are not occupied by the protoplasm of the 

 cells. Moreover, W. Engelmann, since the migrations take place 

 in every possible direction, has drawn the conclusion that the 

 cells run without obstruction between the fibrils of connective 

 tissue, pressing in from one to the other ; various circumstances, 

 however, are in opposition to this view. By careful observa- 

 tion it may be seen that the movements of the migrating cells 

 do not take place with equal facility in all directions. They 

 become constricted at certain points, and these constrictions 

 remain unaltered in position, whilst the several corpuscles force 

 themselves through ; again they appear ' to meet with an ob- 

 stacle, and must pass round it, though the constricting and 

 obstructing substance may be so delicate as not to be visible. 

 But further, if the cornea, or other variety of connective 

 tissue (independently of the cells) consists only of fibrils 

 with intervening fluid, in cases where the injection of an 

 insoluble mass has been effected by means of simple pene- 

 tration, the whole tissue can be split up into fibrils, or, in the 

 case of the cornea, into lamellse, and we may then obtain the 

 sub-cylindrical canals (Bowman's corneal tubes), which often 

 form very distinct plexuses. It is true that the latter, as they 

 appear after injection, present a very unnatural form, being 

 dilated to an enormous extent, on which account, however, they 



