402 ANATOMICAL AND PATHOLOGICAL OBSERVATIONS. 



Ill the villi of tlie intestines of animals, my own obser- 

 vations lead me to believe that absorption by growth and 

 solution is the process which actually takes place. 



The vesicular extremity, like the spongiole of the root- 

 fibril, is the primitive nutritive centre of the villus. The 

 villus originates in a cell. During the development of the 

 villus, this spot or cell was employed only in procuring 

 materials for the growth of the organ. In the perfect animal 

 the formative function of the spot ceases ; its action becomes 

 periodical, active during digestion, at rest during the intervals 

 of that process. The same function is performed, the same 

 force is in action, and the same organ, the cell, is provided 

 for absorjition of alimentary matters in the embryo and in 

 the adult, in the plant and in the animal. The spongioles 

 of the root, the vesicles of the villus, the last layer of cells on 

 the internal membrane of the included yelk, or the cells 

 which cover the vasa lutea of the dependent yelk, and the 

 cells which cover the tufts of the placenta, are the parts of the 

 organism in which the alimentary matters first form a part of 

 that organism, and undergo the first steps of the organising 

 process. 



