37^ HARVEY M. SMITH. 



fatty degeneration of the spleen, lungs and body cavity filled 

 with water, partial paralysis shown by inability to draw up rear 

 legs or to support the body with the right fore leg, and a twisting 

 of the head to the right. This animal showed a fall in carbon 

 dioxide production from 0.1880 down to 0.1239 m S- P er S m - P er 

 hour, and retained approximately the latter rate until death, in 

 spite of a progressive increase in the severity of the symptoms. 

 Other species did not yield much opportunity to study the effects 

 of disease on metabolism. Necturus No. 12 died of fish mould. 

 The determination made on this animal while normal yielded 

 0.0915 mg. per gm. per hour, while a determination made during 

 the active progress of the infection yielded 0.1354 mg. 



6. Motility of the experimental animal may be an important 

 cause of variation in the results obtained. All the animals used 

 were given an hour to get accustomed to the jar before each 

 determination, and there was very little movement in the major- 

 ity of cases. Salientians would shift their position occasionally, 

 but did very little struggling. A few individuals struggled con- 

 siderably during the first test made on them. The results of 

 such experiments were discarded. It is interesting that the 

 struggling resulted in approximately doubling the basal rate 

 of carbon dioxide production. Caudata struggled very little or 

 not at all. 



A few trials were made using curare, which paralyzes the 

 muscles, to see whether more constant results could not be 

 obtained. It was found that the carbon dioxide production of 

 Rana pipiens is thus reduced about 25 to 35 per cent., but the 

 daily variations persist. The method described by Lund (1919) 

 of placing the respiring animal in the jar with the barium hydrox- 

 ide (suspended from the stopper in a basket) was tried on 

 curarized animals. The results checked fairly well with t host- 

 obtained on the same animals by the aeration method, but it 

 was found that a considerable error is introduced by the necessity 

 of removing the animal from the jar at the end of a measured 

 time; a procedure which stirs up the air in the jar and causes 

 loss of carbon dioxide. 



