D. CHEMISTRY AND METALLURGY. 233 



in a large excess of water, the solution being heated to 80 

 Centigrade. After cooling to 14-17, the solution contain- 

 ed not only the substances originally dissolved, but also free 

 nitrobenzoic acid and barium benzoate. The nitrobenzoic 

 acid set free in the reaction, together with the benzoic acid 

 also present, was dissolved by agitation with chloroform or 

 benzene, in which the barium salt is insoluble. In the resi- 

 due, after the solvent was distilled off, the presence of nitro- 

 benzoic acid was proved by means of sodium. In a quan- 

 titative experiment, 1.6592 grammes of pure barium nitro- 

 benzoate was mixed with the theoretical quantity 1.1815 

 grammes of pure benzoic acid, and dissolved in an excess 

 of hot water. The nitrobenzoic acid obtained from the 

 solution was 0.2341 grammes, being 19.81 per cent, of the 

 whole quantity. Additional experiments seem to show 

 that the quantity of the stronger acid set free depends on 

 that of the weaker. 35 (7, VIII., 466, April, 1875. 



COPPER IN THE HUMAN BODY. 



Not long since, in a case of suspected poisoning by a salt 

 of copper, upon analysis a large percentage of metallic cop- 

 per was found in the liver and kidneys. Subsequent re- 

 search, however, proved that copper usually exists as a nor- 

 mal constituent of the animal body, the investigation hav- 

 ing taken place upon fourteen human subjects from the 

 French hospitals. Portions of these were first dried, then 

 carbonized, and the ashes treated for copper, the amount of 

 which varied in quantity from -^ to 1 J milligrammes. The 

 same metal has even been found in the liver of the human 

 foetus. 13 B, Feb. 20, 1875, 186. 



RELATIVE AMOUNTS OF POTASH AND SODA IX MILK AND 

 OTHER FOOD, AND IN THE ENTIRE BODY. 



In pursuing the investigation of the value of salt in nu- 

 trition, Bunge was led to determine the amount of the alka- 

 lies and of chlorine in the most important articles of food, 

 especially in milk ; and, in this connection, the amounts of 

 the alkalies and of chlorine in the entire bodies of a number 

 of animals was also ascertained. Besides analyses of human 

 milk, and of that of herbivorous and carnivorous animals, 

 analyses were also made of the entire bodies of a mouse, 



