CONNECTIVE TISSUE. 47 



It is difficult to determine with certainty whether or 

 not the cells send processes into all of the channels 

 which radiate from the spaces in which they lie ; it is 

 probable that some of the narrow branching bodies or 

 lines noticed above in the gold cornea are nothing more 

 than these branching and communicating spaces in 

 which an albuminous fluid accumulates, which is stained 

 by the gold very much as cell protoplasm itself is. 



We thus see that the cornea is permeated by numerous 

 branching and intercommunicating spaces, and that in 

 these spaces the flat, branching connective-tissue cells lie. 



These spaces are called lymph-spaces^ and what we have 

 been able to demonstrate in regard to the relation of cells 

 to the lymph-spaces in the cornea, by these various modes 

 of preparation, seems to be true, with certain modifica- 

 tions, of the cells in most of the varieties of connective 

 tissue. These cells lie in spaces, sometimes completely, 

 sometimes only partially, filling them. These spaces com- 

 municate with one another, and communicate also, on the 

 one hand, with the blood-vessels, and, on the other, with 

 the lymphatics. Through them lymph-currents pass, 

 bathing the cells and supplying them with nutritive 

 material. 



It is extremely probable that it is through these lymph- 

 spaces exclusively that the white blood-cells travel in 

 their peregrinations through the tissues. We study them 

 in the cornea alone, because the scope of this manual is 

 too limited to admit of such a detailed study of all 

 varieties of connective tissue, and because here the 

 relation of the cells to the spaces is clearly defined. 



Endothelium of the Serous Membranes. The serous 



