<)Q J. Lindhard. 



reading might give a difference of at most 0*02 "/o; the total error 

 in the analysis can scarcely, as mentioned, be taken at more than 

 at the highest 005 ^ о CO 2- Then the percentage of carbonic acid 

 in the dry alveolar air is given calculated from Bohr's formulae 

 As the uncertainty is very small with the amounts composing the 

 calculation, the errors in these numbers will be determined by the 

 possible error, which is introduced by estimating the "dead space" 

 and its variations due to temperature changes. A change in this 

 value of 10 cc. gives in a chance case an error of 007 'Vo or 1-5 ^* о 

 of the number noted. Errors of this kind will however chiefly 

 affect the whole experimental series, they will scarcely have any 

 influence on the form of the variation-curve. 



The next column gives the amount of carbonic acid expired per 

 kilo, and per hour in cc. If we assume that the maximum errors 

 in the elements composing the calculation all tend in the same 

 direction, we must here reckon with a possible error of 4^ 2 **/() of 

 Ihe number noted. 



Errors in the analysis of the inspired air have no importance 

 in this connection. 



The bodily weight was determined by means of a steel-yard; 

 the exactness may be placed at + 0-5 kilo. On days when the 

 weight was not taken, it was determined by graphic interpolation, 

 on the supposition that the rise and fall proceeded regularly from 

 day to day. 



In the last columns are noted the pulse and in many cases the 

 mouth or rectal temperature. 



As a measure of the physiological variations I have used^he 



"standard deviation", calculated from the formula /i = у —^^ 

 whilst the uncertainty in the average is expressed by the probable 

 error derived from the formula ^ 06745 ,— . 



The reasons why the same standards have not been used every- 

 where in the statistics of the variations, is that I wished to empha-' 

 size the difference between the physiological fluctuations of the 

 organism and the errors, or uncertainty, which arise in the constants 

 of the variation-series owing to imperfections in the statistical material. 

 Naturally, the mutual differences between Ihe separate experiments 

 in a series are not all biological variations; as mentioned in the 

 foregoing, there is a possibility of experimental errors up to a cer- 

 tain, given limit, but these errors are in most of the series so small 



1 Bohr: Respiratorischer Gasweciisel ect. iiraunscliweig 1905, p. 139. 



