Notice of some recent additions to Chemistry. 73 



such a source. Liebig quotes the instance of a lean goose, weighing 

 4 lbs., which, in 36 days, gains 5 lbs. weight by consuming 24 lbs. of 

 maize, and yields 3^ lbs. of pure fat. The latter could not be derived 

 from the maize, said Liebig, because maize, according to such experi- 

 ments as had been made upon it before Liebig wrote, did not contain 

 the thousandth part of its weight of fat From whence came the fat? 

 Liebig conceives it to be derived from the starch of the maize, by the 

 simple abstraction of oxygen, and its evolution from the system by 

 respiration, in the form, of carbonic acid. The relation of the carbon 

 to the oxygen in starch is 120 to 100 ; and in fat, 120 to 10. Liebig 

 perceives, in this abstraction of oxygen, a fertile source of animal 

 heat. This idea was strikingly supported by the fact, that bees, when 

 fed upon honey alone, (a substance identical in its composition with 

 starcli,) form large quantities of wax. Now, wax approaches fat in 

 composition, and both yield succinic acid when treated by nitric acid. 

 These ingenious views of Liebig have led Dumas and Payen (L'lnsti- 

 tut 461,) to make a series of experiments, for the purpose of deter- 

 mining the quantity of fatty or oily matter in maize. They have 

 found 9 per cent, of yellow oil to exist in this vegetable ; hence they 

 conclude, when a lean goose eats 24 lbs. of maize, it takes up 2\ lbs. 

 of fatty matter, which, with the fat previously existing in the animal, 

 is sufficient to account for the source of the 3i lbs. of fat. Dumas 

 adds the remarkable intelligence, that hay, such as it is met with in 

 the trusses eaten by animals, contains 2 per cent of fatty or oily 

 matter. He considers that the pasture ox and milk cow furnish 

 always less fat in proportion to its deficiency in the food ; and that in 

 the milk cow, the butter always represents nearly the fatty matter of 

 the food. In the opinion of himself and Payen, the facts derived 

 from farmers and from chemical analysis, agree in proving, that the 

 milk cow constitutes the most exact and most economical method of 

 extracting the azotized and fatty matter contained in pastures. 



It is obvious that these facts, should they enable us to dispense with 

 the explanation afforded by Liebig, of the production of fat from 

 starch, go to substantiate the idea which he was the first to propagate, 

 that the constituents of the blood and of the solid parts of animals 

 generally, before they have undergone transformation, exist ready 

 formed in plants. 



Some years ago. Cap and Henry of Paris stated that urea exists in 

 the urine, in union with lactic acid, under the form of lactate of urea 

 without any water. As, however, Regnault had previously shown that 

 all the salts of urea contained an atom of water, Pelouze was induced 

 to ascertain if lactate of urea could be formed synthetically, by the 

 addition of urea to lactic acid, and by double decomposition with 

 lactate of lime and oxalate of urea. His attempts were unsuc- 

 cessful, and his result in unison with the experiments of Liebig, who 

 could never detect lactate of urea in urine. Pelouze coidd not succeed 



