22 WONDERS OF ORGANIC LIFE. 



gastric juice, is with reason supposed to be 

 derived by the secreting agency of minute 

 glands from the common salt (muriate of soda, 

 or more correctly, hydrochloride of sodium) 

 contained in the blood. If this be the case, 

 the salt must undergo a complete decomposi- 

 tion, and its metallic base, sodium, must enter 

 into some new combination. The chyme into 

 which the gastric juice has reduced the food is 

 an acid semi-fluid, or pultaceous mass, usually 

 of a greyish colour ; it exhibits, however, some 

 differences according to the nature of the food, 

 both as to colour and consistence, but it is 

 invariably acid. In this state it is gradually 

 transmitted from the pylorus, through the py- 

 loric orifice, into the commencing portion of the 

 alimentary canal, termed the duodenum. Here 

 it undergoes further changes. It becomes mixed 

 with the mucous secretion of the canal, with 

 the pancreatic juice, a fluid somewhat resem- 

 bling saliva, and with bile poured drop by drop 

 from a fine duct, which thus conveys the secre- 

 tion of the liver to the duodenum. A singular 

 transformation now begins to take place in the 

 chyme ; it gradually separates into two portions, 

 namely, a whitish tenacious fluid, sometimes 

 opaque, and of an alkaline quality, termed 

 chyle, and a pultaceous residuary portion. The 

 chyle is that portion of the food which is 

 destined to become blood ; the remainder is 

 useless. 



By means of the peristaltic action of the 

 small intestines, both the chyle and the resi- 



