ELABORATION OP NUTRIENT MATERIALS SANGUIFICATION. 205 



such substances as are capable of appropriation to the nutritive process, 

 wln-ther these substances be directly furnished by the external world, or be 

 derived from the disintegration of the organism itself. We have seen that, 

 in the Lacteals, the selecting power is such, that these vessels are not dis- 

 posed to convey into the system any substances but such as are destined for 

 this purpose; and that readily diffusible matters .are absorbed in preference 

 by the meseuteric Bloodvessels. The case is different, however, with regard 

 to the Lymphatics ; for there is reason to believe that they are more disposed 

 than the venous capillaries to the absorption of other soluble matters, espe- 

 cially when these are brought into relation with the skin, through which the 

 Lymphatic vessels are very profusely distributed. 



3. Of the Elaboration of the Nutrient Materials. Sanguification. 



149. The alimentary substances, taken up by the Bloodvessels and Ab- 

 sorbents, seem very far from being capable of immediate application to the 

 nutrition of the body ; for we find that they are not conveyed by any means 

 directly into the circulating current, but that those which enter the Gastro- 

 intestinal veins are submitted to the operation of the Liver, whilst those 

 which are received into the Lacteals are subjected to a kind of glandular 



Fm. 83. 



Cornea of Frog treated with lunar caustic, a, canalicular system. In one place a branched flattened 

 corneal corpuscle with its nucleus is seen ; iu two others arelacunte of the canalicular system, contain- 

 ing nuclei, c, of corneal corpuscles, and d, migrating or wandering cells ; 6, branched channels, which 

 connect the lacunae of the canalicular system. Oc. 3, Obj. 9. 



action within their own system; the newly absorbed materials in both cases 

 undergoing considerable changes, which tend to assimilate them to the com- 

 ponents of the Blood. The Lymphatic System 1 consists of an extensive 

 network of vessels very generally distributed throughout the body, but pres- 

 ent in remarkable abundance beneath the Skin and Mucous membranes. In 

 regard to their origin it has been shown ( 134) that in the villi the lym- 



1 For an exhaustive account of the Anatomy of which, see v. Recklinghausen, 

 Strieker's Human and Comp. Histology, 1870, vol. i, pp. 297-346. See also Klein,' 

 Anatomy of the Lymphatic System, 1873-4, I. Serous Membranes. 



