828 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



diy Avood and set fire to it on cveiy side by lighting it quickly in 

 different places so as to cut off all retreat, to batter down the edi- 

 tice with cannon. The ants thus scattered soon perish in the 

 flames. 



The red ant, Formica rufa, when irritated ejects an acid liquid. 

 This acid which produces a stinging sensation when applied to the 

 skin, is found in a free state in the stinging-nettle (artica urens). 

 The ant being to chemists the first source of this acid, the com- 

 pound received the name of formic acid, but is now made artifi- 

 cially from oxalic acid, and in several other ways. 



Food for Infants. 



Baron Von Liebig was led, from family considerations, to inves- 

 ti^-ate the question of the nutrition of very young children, which 

 involved the analysis of all articles of food for infants. He states 

 that although cow's milk contains the ingredients found in human 

 milk, they are not mixed in the same proportions ; besides, the 

 former is of an acid nature, while the latter has an alkaline reaction. 

 The same objection applies to pap, prepared from flour or other 

 starchy substances, which, although finely ground and dissolved 

 by boiling, has not really undergone such chemical change as to 

 brino- it into the condition for easy assimilation. Liebig claims to 

 have remedied the defects in the common substitutes for human 

 milk, by making the farinaceous substances perfectly soluble by 

 correcting their acidity, and by uniting the substances until in such 

 proportion as to imitate as near as possible food designed by nature 

 for the infant. The recipe which he has devised for the benefit of 

 the public is as follows : 



In a small pan thoroughly mix half an ounce of wheat flour 

 wdth five ounces of milk. In a second vessel mix half an ounce of 

 malt with two ounces of,w\ater and thirty drops of a soluti(.'n con- 

 tainint>- eleven per cent, of carbonate of potassa. Jjct the contents 

 of the small pan be brought slowly to the boiling point, and boil 

 for three or four minutes, then add the contents of the second ves- 

 sel, put on the lid and let the pan remain in a warm place — not 

 exceeding 148° Fah. — for half an hour, when the pan must be 

 ao^ain placed over the fire, until the mixture begins to boil. The 

 contents should then pass through a sieve, which will separate the 

 exhausted bran. The fluid thus produced has the pleasant flavor 

 of fresh bread, and is so sweet as to require no sugar. Children 

 are verv fond of it, and require less of it than of pure cow's milk 



