THE BALANCE OF NUTRITION 



213 



The first practicable form of open circuit apparatus was devised 

 by Pettenkofer **for experiments on man. Its general appearance is 

 shown in Fig. 28. The comparative simplicity of its operation and 



CH+ 



OXIDIZED ABSORBED 

 FIG. 27. Scheme of Pettenkofer respiration apparatus. 



the fact that it could be readily built of any desired size led to its 

 extensive use in investigations upon agricultural animals, notably by 

 Henneberg and Stohmann at Gottingen, Stohmann at Leipzig and 

 G. Kiihn and later Kellner at Mockern. 



FIG. 28. Pettenkofer respiration apparatus. 



Explanatory sketch. {Atwater, U. S. Department of Agriculture, Office of Experiment 

 Stations, Bulletin No. 21.) 



1 Ann. Chem. Pharm., Suppl. Bd. II, p. i. 



