340 GENERAL ANATOMY OF THE ABSORBENT SYSTEM. 



very much the appearance of a mesh of arteries and veins, for 

 which, no doubt, they have been sometimes mistaken. 

 But the lymphatic net-work is evidently seated above the 

 blood-vessels, for if the latter be subsequently injected, they 

 never rise up so as to cover the former; and where the blood- 

 vessels have first been filled, the lymphatics may be subse- 

 quently injected above them^. In the mucous membranes 

 provided with epithelium, the situation of the superficial 

 absorbent net-work is precisely the same as in the skin ; but in 

 mucous membranes unprovided with epithelium, or rather in 

 which the epithelium exists in a state of undried mucus, the 

 situation of the lymphatic net-work is more naked, a condition 

 which is eminently favorable for the accomplishment of the 

 function of absorption. 



Each of the villi of the mucous membranes, are now believed 

 to be nothing more than delicate elevations of the mucous 

 membranes, comprising separate loops of the sanguineous and 

 absorbent vessels, and probably nervous fibrils, covered by a mu- 

 cous pellicle. The lymphatic vessels have the same mode of 

 origin in the lining membrane of the cavities of the heart, as well 

 as on the exterior of that organ as has been proved by Lauth, 

 Bonamy, and Cruveilhier,* who succeeded in injecting them. 

 The origin of the lymphatic vessels, from the midst of the 

 nervous, muscular, and glandular structures, is not, from the 

 very nature of the parts, easily susceptible of demonstration. 

 Nothing positive, therefore, is known in regard to it, and it is 

 most probable that Mascagni was right in his suggestion, that 

 the numerous vessels which issue from the parts, originate in 

 the cellular tissue which forms the woof of the organs. 

 The origin of the lymphatics from the cellular tissue and 

 serous membrane which is but a modification of the cellular, 

 is certainly more general than that from any other tissue of the 

 body, and there is much reason to believe, that it is the princi- 

 pal point from which they arise the soil in which their radi- 

 cles are found ; and in the different organs of the body where 



* Anal. Speciale, torn. iii. 



