96 ALIMENTATION. 



large quantity. The importance of porosity in improving 

 the digestibility of bread has been illustrated by experiments 

 on animals. Dr. Hammond caused a dog, in which he had 

 established a gastric fistula, to eat successively equal weights 

 of vesiculated and compressed bread. The first was di- 

 gested in two hours and fifteen minutes, and the latter, in 

 three hours and thirty-five minutes. 1 



In the manufacture of good bread it is absolutely neces- 

 sary to render it porous by the generation of gas in the dough 

 before baking ; but this may be effected without fermenta- 

 tion. Unfermented or aerated bread may be made by mix- 

 ing carbonate of soda with the flour and adding hydrochloric 

 acid in the water, or by using water charged with carbonic 

 acid. The use of bread made in this way is simply a ques- 

 tion of taste. 



Flour simply mixed with water and baked, called in this 

 form ship-bread, sea-biscuit, hard-tack, etc., will keep almost 

 indefinitely. It requires thorough mastication, and is not 

 so easily digested as ordinary bread, but apparently all the 

 nutritive principles are preserved. The other forms of bread, 

 rolls, muffins, etc., are simply articles of luxury, and do not 

 differ much in their nutritive properties from ordinary bread. 

 The various forms of cake are made of flour, with the addi- 

 tion of butter, lard, eggs, sugar, and sometimes dried fruits. 



Although bread has been called the staff of life, it seems 

 incapable by itself of supplying for an indefinite period all the 

 nutritive demands of the human organism. The same may be 

 said, however, of every single article of food, whether it be- 

 long to the animal or vegetable kingdom ; for man requires 

 a much greater variety of alimentary principles than the in- 

 .ferior animals. While it is possible that life might be barely 

 sustained on bread and water, experience with regard to this 

 diet in prisons and elsewhere has demonstrated that it is in- 

 capable of maintaining the body in full vigor. That this is 



1 HAMMOND, Treatise on Hygiene, Philadelphia, 1883, p. 519. 



