ON THE INTESTINAL VILLI. 399 



conduces towards the performance of the function of these 

 follicles. 



The villi, being now turgid with blood, erected, and naked, 

 are covered or coated by the whitish-grey matter already 

 described. This matter consists of chyme, of cast-off epithelia 

 of the villi, and of the secreting epithelia of the follicles. The 

 function of the villi now commences. The minute vesicles 

 which are interspersed among the terminal loops of the lacteals 

 of the villus, increase in size by drawing materials from the 

 blood through the coats of the capillary vessels, which ramify 

 at this spot in great abundance. While this increase in their 

 capacity is in progress, the growing vesicles are continually 

 exerting their absorbing function, and draw into their cavities 

 that portion of the chyme in the gut necessary to supply 

 materials for the chyle. When the vesicles respectively 

 attain in succession their specific size, they burst or dissolve, 

 their contents being cast into the texture of the villus, as in 

 the case of any other species of interstitial cell. 



The debris, and the contents of the dissolved chyle-cells, 

 as well as the other matters which have already subserved 

 the nutrition of the villus, pass into the looped network of 

 lacteals, which, like other lymphatics, are continually em- 

 ployed in this peculiar function. As long as the cavity of 

 the gut contains chyme, the vesicles of the terminal extremity 

 of the villi continue to develope, to absorb chyle, and to 

 burst, and their remains and contents to be removed along 

 the lacteals. 



When the gut contains no more chyme, the flow of blood 

 to the mucous membrane diminishes, the development of 

 new vesicles ceases, the lacteals empty themselves, and the 

 villi become flaccid. 



The function of the villi now ceases till they are again 

 roused into action by another flow of chyme along the gut. 



During the intervals of absorption, it becomes necessary 



