130 DIGESTION 



30. The albuminoid substances are speedily attacked and 

 digested by the gastric juice. From whatever source they are 

 derived, vegetable or animal, they are all transformed into the 

 same digestive product, called pepimie. This is very soluble 

 in water, and is in part absorbed by the blood-vessels of the 

 stomach. After a longer or shorter time, varying from one to 

 five hours, according to the individual and the quantity and 

 quality of his food, the stomach will be found empty. Not 

 only the unabsorbed digested food, but also those substances 

 which the stomach could not digest, have passed little by little 

 through the pylorus, to undergo further action in the intestines. 

 At the time of its exit the digested food is of a pulpy con- 

 sistence, and dark color, and is then known as the chyme. 

 (Head Notes 5 and 6.) 



5. Indigestible Matters. " Children sometimes swallow coins, but- 

 tons, etc., and so cause great alarm. There is little real ground for appre- 

 hension under these circumstances, unless the coins are bronze. If the 

 latter, there is some cause for fear that copper poisoning will ensue, and 

 the ready passage of the coin is desirable. This is best effected by meals 

 of figs or pudding, in which the coins are imbedded, and so passed harm- 

 lessly. As to bulk, whatever will go into the stomach will pass the 

 various straits and emerge again." Fothergill. 



6. Experiment. Gastric Juice. The action of the gastric juice upon 

 the albuminoids can be readily demonstrated outside of the body. Tor 

 this it is necessary to prepare a solution of pepsin and a solution of hydro- 

 chloric acid. The first of these may be made in one of two ways. The 

 simplest of these is to obtain some pure pepsin from the druggist, and 

 dissolve of this thirty grains in four ounces of pure glycerin ; the other, 

 but more complicated way, is to obtain a pig's stomach, dissect off the 

 mucous membrane, mince finely and add six ounces of glycerin, set aside 

 for a week and strain through muslin. The solution of hydrochloric acid 

 should be of the strength of two parts per thousand, which would be 

 about two or three drops of the strong acid to four ounces of water. 



Demonstrate that neither the solution of pepsin nor the hydrochloric 

 acid alone have the power to digest albuminoids. 

 Prepare three test-tubes as follows : 



1. Into one put about a teaspoonful of -the pepsin solution, and add a 

 small piece of the white of a hard-boiled egg. 



2. Into the second test-tube put a teaspoonful of the dilute hydro- 

 chloric acid, euid add again a small piece of the white of the egg. 



3. The third test-tube fill half with the solution of acid, add half a tea- 

 spoonful of the pepsin solution, and again a small piece of the egg. 



30. Albuminose ? The process ? Chyme ? 



