CHARACTER OF THE KATABOLISM. 83 



quotient. With practically all of the quotients which are inclosed in 

 brackets we find very great increases in the carbon-dioxide production 

 over that of the preceding period; hence we may ascribe at least a 

 portion of this change in the quotient to an excess carbon-dioxide 

 excretion. It is not impossible that a certain amount of the carbon 

 dioxide thus excreted may be due to actual over-ventilation of the 

 lungs of the infant, produced by excessive crying; this can not, how- 

 ever, account for the entire increase. 



For a partial explanation of these variations in the carbon-dioxide 

 production, we may with profit examine the kymograph records accom- 

 panying each period. It is impracticable to publish all of the records 

 obtained in this series of observations ; accordingly two skilled observers 

 have examined them independently and have indicated the relative 

 activity by ascribing a letter to each individual period. This classi- 

 fication is not intended as a comparison of the activity of one infant 

 with another, nor do the letters designate arbitrary degrees of muscular 

 repose. They apply only to the activity of each infant by itself and 

 show the muscular repose of the individual periods as related to that 

 of the other periods, A being used to designate the greatest degree of 

 muscular repose. If there are two periods in an observation when the 

 muscular repose is of exactly the same degree, they are given the same 

 letter. (See infant No. 82.) The estimations made by Observer I 

 and Observer II never differ more than one unit in classification and 

 usually they are identical. It will be seen that in practically all of the 

 instances in which abnormally high quotients were found, there was 

 a great increase in the activity as shown by the kymograph record. 

 While a variation in the degree of muscular repose is not always 

 accompanied by a variation in the respiratory quotient, nevertheless 

 this is true in the majority of cases. 



In view of these considerations, we must accept with reserve the 

 respiratory quotients which do not lie within reasonable limits of the 

 average quotient for the day. If the infant organism were surcharged 

 with glycogen we would normally expect to find a high respiratory 

 quotient shortly after birth, with a gradual decrease throughout the 

 day. A critical examination of all of the values in table 10 shows 

 a distinct, though slight, tendency for the quotient to fall off during 

 the day; on the other hand, the initial quotients are not extremely high, 

 being for the most part considerably less than 0.90. We may there- 

 fore properly conclude that while the quotients have a tendency to 

 decrease as the period of inanition lengthens, since the quotients are 

 rarely as high as 0.90, even when obvious technical errors are eliminated, 

 we can not infer that the katabolism is chiefly that of carbohydrate 

 during the observation period. 



According to the table of Zuntz and Schumburg, a non-protein 

 respiratory quotient of 0.90 corresponds to a combustion in which 

 66 per cent of the total energy is derived from carbohydrate and 34 



