150 LYMPHATIC SYSTEM. 



faction ; but what becomes of them after they have got to the 

 cellular coat is not so easy to determine : in five or six dif- 

 ferent experiments which I have made, the mercury passed 

 from the lacteals into the cells between the muscular coat and 

 the internal, and spread from cell to cell very uniformly over a 

 great part of the intestine, although but little force had been 

 used, and although there was nothing like extravasation in any 

 other part of the intestine. Upon inverting the intestine, 

 after thus filling its lacteals, the mercury, on being pressed, 

 was in many parts driven into small vessels upon the internal 

 coat, or villous, as it is called. From whence it would seem 

 that this cellular network was a part of the lymphatic system 

 in this animal. It might indeed be supposed to be mere ex- 

 travasation, but that it is rather a part of the lymphatic 

 system appears from the following considerations : first, from 

 the regularity in the size of the cells ; secondly, from the little 

 force used in the experiment, and from there being nothing 

 like this appearance in the cellular membrane between the 

 peritoneal and the muscular coat, where extravasations were as 

 likely to happen ; thirdly, from my having been able, after in- 

 verting the intestine, to press the quicksilver from the cells 

 into the very small vessels upon the internal coat. But I 

 must confess these facts would not be sufficient to determine 

 whether these cells were or were not a part of the system, did 

 not the analogy of the same part in fish clearly prove it. For 

 in the cod, instead of the cellular network, as in the turtle, 

 there is a network of vessels (of which a description shall be 

 given in the next chapter), so that I have now no doubt but 

 that those cells are parts of the lymphatic system, and that the 

 small absorbent vessels of the internal coat pour their fluid 

 into this network, from which it is conveyed by the larger 

 lacteals. 





