CONNECTIVE TISSUE IN AMPHIBIA 455 



between ground substance and cell bodies is so clear that the 

 cell processes can be differentiated from the ground substance 

 and traced to their definite endings, even though they may be 

 drawn out extremely fine. Attention should also be called to 

 the color reactions of the muscle tissue which bounds the ground 

 substance. It will be noted that the bundles or muscle fibers 

 show the characteristic color reaction of the cytoplasm of the 

 mesenchyme cells lying in the ground substance. These results 

 demonstrate that the Mallory connective tissue stain differ- 

 entiates definitely the living substance, present in the cells 

 and in the muscle tissue, from the intercellular ground substance. 

 It is worth while to note in this connection that Mall says'' 

 "In specimens of this kind it is easy to view these cells with their 

 endoplasm as the connective-tissue cells and the exoplasm of the 

 syncytium as the intercellular substance were not the develop- 

 ment of the syncytium taken into consideration." And also^ 

 "while my results are now decidedly in favor of Flemming's 

 view, the reader will soon see that if other methods and inter- 

 pretations are employed (which I now consider false), it will 

 be quite as easy to see the fibers developing between the cells 

 as within them." Inasmuch as in the present work the study 

 of the various stages has shown, in general, that the formation 

 of the ground substance takes place before there is any attempt 

 to form a syncytium by the mesenchyme cells — in fact before 

 they have left the cell groups, wandered into the ground sub- 

 stance and there assumed the irregular shapes characteristic 

 of mesenchyme cells — it is evident that the formation of the 

 ground substance cannot be due to a cytoplasmic syncytium. 

 This fact leads definitely to the conclusion, as Mall suggests 

 above, that the cells with their endoplasm are the connective 

 tissue cells complete and the material in which they lie is not 

 exoplasm but an intercellular substance or ground substance. 

 The cells which move into the common, intercellular ground 

 substance are separate entities; not a part of it but apart 

 from it. 



«Mall, 1902, p. 336. 

 'Mall, 1902, p. 330. 



