131 



into error, by the nervous papillae of the inner membrane of the canal, 

 swollen by the determination of blood attending irritation, the natural 

 consequence of the friction of the alimentary substances. The inhaling 

 faculty belongs, not only to the orifices at the extremity of each radicle, 

 but, likewise, to the lateral pores, which are infinitely numerous, in the 

 parietes of the vessels*. 



XLIII. After arising on the surface, and in the interior of the body, 

 by radicles in close contact, the lympathetics creep and coil themselves, 

 describe numerous curves, unite, then divide, and presently unite again, 

 and from these numerous inosculations, there results a net-work, with 

 close meshes, forming, with that of the blood-vessels, the texture of the 

 cellular tissue and of the membranes. 



Each lamina of cellular tissue is, in the opinion of Mascagni, nothing 

 but a mesh- work of lymphatics the texture^of the membranous and 

 transparent tissues, as the pleura and the peritoneum, resembles that of 

 the lamina of the cellular tissue; in fine, the same vessels form the ba- 

 sis of the mucous membranes which line the internal parts of the alimen- 

 tary canal of the trachea and urethra. The Italian anatomist succeeded 

 in filling, with quicksilver, all the tissues which he considered as lympha- 

 tic 5 but Ruysch, in his admirable injections, reduced all the membranes, 

 and the lamina of the adipose tissue, into a net-work purely arterial, of 

 which the meshes were so very closely united, as to leave spaces that 

 could scarcely be perceived by the microscope, and from his preparations 

 he inferred, the arterial capillary vessels, singularly divided and convo- 

 luted, form the basis of cellular and membranous tissues. To satisfy 

 one's self, that neither the pleura nor the peritoneum are formed as Mas- 

 cagni or Ruysch imagined, one need only consider, that arterial exhalation 

 and lymphatic absorption take place, from the whole extent of internal 

 surfaces, and that these two functions prove the existence of both arte- 

 ries and absorbents, in those membranes, and in the cellular tissue. The 

 prejudices of those two anatomists, so celebrated, the one by his study 

 of the absorbents, and the other by his beautiful injections of the most 

 minute arteries, are to be attributed to the importance which we are 

 pleased to assign to the objects which particularly engage our attention, 

 and likewise to the distension of the minute vessels by the injection : 

 these being distended beyond their natural state, compress and conceal 

 the neighbouring parts. 



The lymphatics, after emerging from among the cellular substance, 

 unite into trunks sufficiently large to be distinguished from the lamina of 

 that tissue. These trunks proceed towards certain parts of the body, 

 there they become united to other trunks, follow a parallel course, and 

 frequently communicate together. The lymphatics are not single in their 

 course, as the arteries and veins; they collect together, form fasciculi of 

 different sizes, some of which are deep seated and accompany the blood- 

 vessels, while others of them are more superficial, corresponding to the 

 subcutaneous veins of the limbs, and, like them, lying between the skin 

 and the aponeuroses, and in greatest number, on the inner side of the 



excited by the stimulus of the fluid to an erection ofits orifice, in consequence of which 

 the latter is rendered pervious. The fluid being now introduced, the vessel contracts, 

 and propels its contents in succession along its course to the ultimate destination. 

 Chapman. 

 * See APPENDIX, Note Q 



