AETIFICIAL PRODUCTION OF FAT. 81 



One of these illustrative cases still remains. It belongs to the class 

 of changes now under consideration, and deserves a prominent examina- 

 tion from its connection with duodenal digestion. It is the production 

 of fatty bodies from starch and sugar. 



Physiological considerations assure us that there are circumstances 

 under which oils and fats can be formed from starch and p roduction of 

 sugar in the system. Animals can be fattened by feeding fats from ear- 

 on potatoes, or other such food, in which the quantity of oil y rj 

 is quite insignificant. Bees can make wax, which strictly belongs to the 

 group of fats, though they are fed on pure white sugar. 



Such results can be artificially imitated. If a strong solution of sugar 

 be mixed with a small quantity of casein and powdered chalk, and ex- 

 posed to a temperature of more than 80, carbonic acid and hydrogen are 

 evolved, and butyric acid forms as the butyrate of lime. This acid sub- 

 stance is a colorless oily liquid, having the odor of rancid butter, in 

 which indeed it exists. 



From a review of all the preceding facts, we may conclude that a nitro- 

 genized substance secreted by the follicles of the stomach, Contrast of 

 and undergoing incipient oxidation, acidulated with hydro- 

 chloric acid obtained by the decomposition of common salt, tion. 

 or with lactic acid produced by a continuation of salivary digestion, has 

 the power of dissolving coagulated albumen, and generally those articles 

 of food which belong to the nitrogenized class ; that -this goes on in 

 the stomach, it being the function of that organ to effect the digestion of 

 this kind of food, and thereby contribute to the general nutrition of the 

 system. The muscular tissues are supplied from this source, and by the 

 stomach their waste is repaired. 



Another and distinct digestion takes place in the intestine, commenc- 

 ing immediately after the food gains the duodenum. It too is brought 

 about by the action of a special liquid, a mixture of the pancreatic and 

 intestinal juices. The chemical reaction of this juice is alkaline ; in this 

 respect it is therefore antagonistic to the gastric juice. This quality is 

 due to the soda it contains, a substance derived co-ordinately with hy- 

 drochloric acid from the decomposition of common salt. The digestion 

 of starchy and saccharine bodies is thus effected by dividing them so as 

 to produce lactic acid. 



This done, common salt is reproduced by the commingling of the gas- 

 tric, biliary, and pancreatic products together. The salt is carried by the 

 absorbents into the interior of the system, to be again decomposed. 



Moreover, the pancreatic and enteric juices reduce the oleaginous and 

 fatty bodies to the condition of an emulsion, or, if they be not present 

 in the food, give origin to them in the way just described. 



The reaction of the intestinal contents not only differs in different por- 



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