i'HEOHIES OF DIGESTION. 49 



ding to the nature of the aliments, for in fact there seems 

 to be as " many species of chyme as there are varieties of 

 of food." The chyme when formed is moved towards 

 the pyloric orifice into which it enters, and new portions 

 ar< brought into contact with the stomach, until the whole 

 has undergone this change. 



Emily.- But can't you say a little more definitely, 

 how this marvellous phenomenon has been produced. 

 I hope it is not wholly involved in obsurity if the curi- 

 osity of physiologists has been so strong as mine, I am 

 sure they have not left its extrication unattempted. 



Dr. B. If you could see but a moiety of the discus- 

 sions and speculations which this subject has occasioned, 

 you would be convinced that for once at least, men had 

 proved themselves in respect to that praise-worthy spirit 

 of curiosity, not unworthy of being mentioned in connex- 

 ion with your own sex. The older physiologists were 

 utterly ignorant of the true nature of chymification, al- 

 though they made divers theories to explain it. Some 

 of them imagined it to be a sort of concoction or stewing 

 of the food, and this continued to be a very common 

 opinion till the revival of learning in modern Europe. 

 The chemical philosophers who had their day in the 

 beginning of the last century, banished this theory for- 

 ever, and promulgated the more fashionable one, by 

 which this process was considered to be neither more 

 nor less than a true fermentation. In a short time this 

 doctrine was eclipsed by that of the mechanical philos- 

 ophers, who regarded chymification as nothing more 

 than mere trituration or grinding, the food being ground 

 up by the walls of the stomach which were thought to 

 be endowed with immense power. One of the suppor- 

 ters of the trituration theory even calculated the force 

 with which the coats of the stomach acted in digestion, 

 which he gravely estimated at 12,900 Ibs. The cele- 

 brated Dr. Hunter in his laconic way, has humorously 

 exposed the absurdities of these theories, while he has 

 pointed out their common source of error. " Gentle- 

 5 



