40 GRAHAM LUSK 



persons. But tins application of the method of Bonsgingault is too im- 

 perfect to establish definitely incontrovertible results in science-." 



It might he aiKlc*! at this point that Lie-big in 1SI5 found that nine- 

 Tenths and more of the heat measured by the calorimeters of Dulong and 

 r,f Despreiz could Ie accounted for from Ihc oxidation of carhon and 

 hydrogen calculated according to the method of Lavoisier. The more 

 modern caloric values f>r hydrogen were here employed as later in 18.*>^ 

 hy Gavarret 



Liehig also points out that if one of the dogs experimented upon hy 

 Dulong had really eliminated the quantity of nitrogen gas Dulong had 

 reported, the animal in seven days would have expired as nitrogen gas 

 the amount of that element contained in its hair, skin, flesh and blood, and 

 at the end of the period would have been merely a mass of mineral ash. 



Eegnault (1810-1878). Henri Victor Regnault was born in Aix-la- 

 chapelle, and in 1S4O became professor of physics and chemistry at the 

 University of Paris. In 1847 he became also chief engineer of mines; 

 in 1854 was director of the Sevres porcelain manufactory. He was a 

 strict disciplinarian of students and up to the outbreak of the war in 

 1914 his memory was Leld in tradition as representative of the highest 

 pedagogical severity. 



In 1840 RegmntJt and Eeiset published their celebrated monograph 

 upon the respiration of animals. The apparatus which they used consisted 

 of a closed system, from which the carbonic acid produced by an animal 

 placed within the system could be absorbed, and into which oxygen could 

 be admitted as the atmospheric air was consumed by the animal. This is 

 the "closed system of Regnault and Reiset," the principle of which is 

 employed in modem, calorimeter work (vide Atwater and Benedict, 

 1005)*. 



The results obtained were usually accurate and their interpretations 

 were within the compass of the knowledge of the time. 



Their main conclusions as they enumerated them, together with some 

 of their experimental data, are presented in the following abstract: 

 For animals r.f warm blood, mammals and birds: 



1. Xormaliy nourished animals constantly expire nitrogen but the 

 quantity eliminated is very small, never exceeding two per cent and often 

 being less than one per cent of the total oxygen consumption. 



2. If animals fast they frequently absorb nitrogen. The proportion 

 of nitrogen absorbed varies within the same limits as the exhalation of 

 nitrogen by animals regularly fed. This absorption of nitrogen takes 

 place in almost every instance in the case of birds but scarcely ever in 

 mammals. . . . 



(In experiment 10 performed on a rabbit the quantity of nitrogen 

 absorbed was 0.08 per cent of the quantity of oxygen absorbed. In the 

 text of the article they remark that the enormous elimination of nitrogen 



