NORMAL PROCESSES OF ENERGY METABOLISM 529 



at any desired level. In the excessively warm days of summer, it is neces- 

 sary to place ice in the tank. 



An apparatus devised by the writer, and constructed simultaneously 

 with the last for use in Bellevue Hospital, New York, follows the same 

 general principles as that just described, but employs as a means of con- 

 trolling the temperature the electrically regulated incubator of Freas. 



Fig. 8. Respiration incubator (Murlin). 



For this reason it has been called a "respiration incubator," and can 

 be used as an incubator for premature infants independently of its features 

 as a respiration machine (Murlin (d) ). 



d. Apparatus for Very Small Animals. With very small animals, their 

 eggs or larval stages it is not necessary to circulate the air through absorb- 

 ers. The absorption of oxygen can be recorded by a change of pressure and 

 the carbon dioxid can be readily absorbed by means of a suitable solution 

 of alkali. Several forms of apparatus constructed on these principles have 



