SECTIONS OF FOODS AND TEXTILES. 171 



Carbonic acid is a colorless gas, heavier than air. The protein, fats, 

 and carbohydrates of the daily income contain 10.8 ounces of carbon. 

 Of this 0.2 of an ounce goes to form urea, and the rest combines with 

 the oxygen of the air inhaled and forms 38.8 ounces of carbonic acid, 

 which is given off through the lungs. 



(4) A day's ration. 



BEEFSTEAK OP A DAY'S RATION 



8 OUNCES. 



The principal nutrients of meat are protein and fat. 

 The composition of a round steak of beef, free from 

 bone, is as follows : 





In 100 parts 



In 8 ounces 



NUTRIENTS 



( Protein, chiefly myosin and syntoniii 23.0 

 2 Fats 9.0 

 ( Mineral matters 1.3 



1.9 ounces 

 0.7 " 

 0.1 " 



WATER 



66.7 



5.3 " 



(5) Composition of a loaf of bread. 



PROTEIN OF A POUND OF BREAD 



1.4 OUNCES. 



The protein of bread is chiefly gluten, the proportion of 

 which is variable. An average of several analyses showed 8.9 

 per cent., the proportion shown. 



The protein of wheat consists of several albuminoids, the principal of which are gluten 

 casein, gluten fibrin, gliadin, and mucedin. These together are known as gluten or vege- 

 table albumen. They are similar to the albuminoids of meat. Gluten imparts tenacity to 

 the dough and enables it to retain the gaseous products of fermentation with some force, thus 

 pioducing a porous and light bread. 



(6) Constituents of a mackerel weighing 1 pound. 



PROTEIN OF A POUND MACKEREL 



1.6 OUNCES. 



The flesh of a mackerel of average composition, weighing 

 one pound, would contain about 1.6 ounces of protein, the 

 quantity shown. 



The protein of the flesh of fish is very similar to that of the flesh of domestic animals used 

 for food. It is found mostly in the muscles and consists of several compounds. The prin- 

 cipal of these compounds is called myosin, the basis of muscle of man and animals. The 

 protein compounds, sometimes called " flesh formers " or " muscle substance," are physiolog- 

 ically the most important and pecuniarily the most expensive ingredients of food. 



