Dr Alison on the Principle of Vital Affinity. 281 



which seems to imply that it is decomposed, and its elements 

 thrown into other combinations, in the course of the cellular 

 action which attends the absorption of chyle. 



In like manner, the formation of fatty compounds out of 

 starch, or its kindred principles, as illustrated by the recent 

 precise observations on the formation of wax by bees, and 

 the formation of gelatine in the living animal, are undoubted 

 instances of chemical trani>formations thus effected. The pre- 

 cise scene of these transformations is not yet ascertained, but 

 we have strong reason, from analogy, to suppose that they 

 are effected in the course of the circulation. And as we are 

 certain that the greatest of all the chemical changes which 

 are peculiar to living beings are effected within the cells of 

 vegetables, it seems in the highest degree probable, that the 

 corpuscles or cells (both red and white) which form so large 

 a part of the blood of animals, are concerned in the chemical 

 transformations which take place in blood ; and therefore, 

 that we are to regard organized and living cells as the agents 

 or instruments employed by nature in effecting all those 

 chemical changes which are peculiar to the state of life. And 

 if we consider this principle as established, it goes far to ex 

 plain several facts, long regarded as obscure, in regard to 

 the structure and position of the lymphatic and lacteal ves- 

 sels. We know that the mode of origin of these vessels gives 

 time and opportunity for cellular action {i. e.^ the develop- 

 ment, growth, and rupture of cells), and consequent chemical 

 changes, at their extremities ; we know that such cellular ac- 

 tion does in fact go on there, particularly in the lacteals; 

 and we know that the substances absorbed there, and pro- 

 bably elsewhere, by these vessels, are in fact altered, and so 

 far assimilated, in the act of absorption ; as in the case, al- 

 ready mentioned, of bile absorbed from the intestines. Thus 

 we are led to see the importance of these vessels being placed 

 at all points where substances are to be absorbed, which are 

 foreign to the animal economy, or require chemical change, 

 in order that they may be introduced with safety or good 

 effect. Hence, also, we see the use of the lymphatic glands, 

 at which another opportunity for cellular action, for chemi- 

 cal changes an4 assimilation, according to the observations 



