146 ASSIMILATION AND ITS ORGANS. 



send it down stairs, where it is received or wanted by the next 

 chamber ; which in like manner exhausts, digests, and detrudes it. 

 In this wise the successive digestion by the agency of the succes- 

 sive muscular coats, is the means of sending the aliment from stage 

 to stage of its useful journey. 



In health however there is no intrusion from above downwards, 

 which is not commanded by an equal attraction from beneath. The 

 food lies upon the plate, and the man and the mouth voluntarily take 

 it. Eating and drinking are quad voluntary all the way down as in this 

 first instance at the top. Whatever violence of supply is superadded, 

 is the answer to a greater urgency of demand ; for the intestines be- 

 come bigger as they proceed, and more and more ravenous. The 

 lower belly, hollow by nature, calls to the upper with loud Halloos. 

 But the consequence of any force unsolicited from below, is seen 

 in a lively image when food is thrust down our throats without our 

 consent, in which case we cannot swallow it. And just as jealous 

 as the man, is the stomach, and are the intestines, of having any- 

 thing thrust down their throats. So food to which we are averse, 

 rouses the hostility of the whole line, and is successively unswal- 

 lowed by part after part; for swallowing in its finer meanings, 

 blends with digestion. Many facts prove this case, and also that a 

 series of instincts or voices are located in the tube, which command 

 or refuse particular aliments. 



But the series of parts has a series of powers whose existence is 

 written upon the forms of the organs. The velvety palpation of 

 the food by the lips, its reduction by the teeth, the warm squeeze 

 of parts and juices by the tongue, are again the exemplars of all 

 the forces and actions which succeed them. There is however 

 nothing so violently physical in any other part of the tube as in 

 the mouth, but motion, warmth, long delay, incessant working, and 

 the semi-chemical forces of certain fluids, perform changes which 

 arc in reality far more sweeping, without the assistance of any rude 

 agency. Nevertheless from the stomach the muscular powers and 

 opposing surfaces become more forcible and urgent, and thrash out 

 the last grain from the chaff with somewhat of indignant exaspera- 

 tion. 



As the point of this series of muscular forces there is a corres- 



