ABSORBENT SYSTEM OF MAMMALIA. 



505 



391 



not prevent the effects of the ever-present, ever-active force which 

 manifests itself, e.g., in the combination of an alkaline solution 

 with a less alkaline fatty, emulsion 

 previously separated by such mem- 

 brane : and the cell-wall would offer 

 much less physical resistance to the 

 diffusive interchange than the mem- 

 brane used, e.g., in Matteucci's ex- 

 periments. 1 But, besides the act ot 

 physical imbibition, with which the 

 intussusception of aliment by mo- 

 nads or nucleate cells is closely re- 

 lated if not identical, there are also 

 assimilative changes effected by these 

 organites. Viewed by the microscopic 

 aids of the last century they were 

 thought to be orifices by which the 

 chyle was sucked up and then con- 

 veyed by beginnings of the lacteal ab- 

 sorbents to the central space or ( trunk,' 

 of which Cruikshank saw ' but one in 

 each villus ' of a female who had died 

 suddenly a few hours after a full meal (clxxviii"): occasionally 

 two have been seen with looped unions in one villus : in Mam- 

 mals with broader villi the chyle-cavity is reticulate. These 

 trunks are, however, the first de- 

 finite absorbent channel, and, ac- 

 quiring proper walls, unite together 

 at the roots of the villi to form a 

 network at the areolar basis of 

 the mucous membrane, whence 

 branches proceed to perforate the 

 muscular coat, and take a trans- 

 verse course to the line of attach- 

 ment of the mesenteric layers. There are, also, superficial ab- 

 sorbents of the serous coat, which affect a longitudinal course and 

 unite with the lacteals in their passage to the areolar interval of 

 the layers of the mesentery : here they traverse the mesenteric 

 glands, and progressively unite into a plexus surrounding the 

 superior mesenteric artery. The lacteals and lymphatics from 

 the caecum and colon, which also traverse absorbent ganglions or 



Intestinal villus, Dog, magn. 400 diam 

 two hours after feeding, cxlviii" 



392 



Epithelial cells of a villus, during absorption 

 of fat, magn. 350 diam. cxlvih". 



clxxvii". p. 104. 



