52 



Messrs. Dreyer, Ray, and Walker. 



[Sept. 30, 



upon animals (W"/A = k) if one gives n the value § or - 67 instead of 

 0'70-0*72, as we have found it to be. This latter formula is a rational 

 formula, since it indicates, as has already been pointed out, that the aortic 

 area (like the blood volume) is a function of the body surface. 



Table XIII. — Man (grouped). Thoma's Observations.* 



Group. 



Number of individuals 

 in group. 



Average body weight. 



Average radius of aorta. 



CO 



II 

 II 



M 



ST 



00 

 <N 

 II 



li 



NT 



t3 



C5 ■ CO 



S y co 



5 ii li 



o w 



Difference between 

 aortic radius calcu- 

 lated and observed. 



T3 



_0j 00 



"S • lb 

 J M II 



I E w 



h ,, cm 

 u 



■J3 „ II 

 § fc « 

 < 3 



Difference between 

 aortic radius calcu- 

 lated and observed. 







grm. 



mm. 









per cent. 





per cent. 



A 



7 



8,941 



6-1 



39-4 



54-6 



6-16 



0-97 



605 



083 



B 



9 



11,950 



6-7 



39-7 



56-0 



6-78 



1-18 



6-71 



015 



C 



5 



13,630 



7-25 



35-8 



51-8 



7-09 



2-26 



703 



313 



D 



3 



17,510 



7-65 



39-1 



56-4 



7-70 



0-65 



7'68 



039 



E 



4 



43,250 



10 -2 



40-8 



61-9 



10-41 



2-02 



10-58 



3-59 



F 



5 



49,000 



11 -2 



34-9 



53-9 



10-86 



3-13 



11-06 



1-27 





38-3 



55-8 





1-70 





1-56 



* Thoma's data are printed in light type. The figures calculated by us are printed in heavy- 

 type. 



In Table XIII we have calculated K for Thoma's figures from the formula 

 W/r n = K, first giving n the value 3 as in Thoma's formula, and then 

 giving it the value 2"82, which corresponds to % — 071 in our formula, 

 and is the best n for Thoma's observations. It then appears that if the 

 aortic radius be calculated by means of these values of K the average 

 percentage deviation between r calculated and r observed is l - 70 when n 

 has the value 3, while it is only T56 when n has the value 2"82. Moreover, 

 if the appropriate allowance be made for the number of individuals in each 

 group the figures become 1'65 with n taken as 3, and T35 with n taken 

 as 2'82. It will, of course, readily be apprehended that differences of this 

 amount in the radius assume a considerable importance when calculations 

 are made by area {i.e. ttt 2 ), as is necessary in referring the aortic area to the 

 body surface. 



In Table XIV are tabulated our main results arranged in such a manner 

 as to show at a glance the range of weight, the best n, the value of k, the 

 percentage deviation, and so forth for each species of animal. It will be 

 seen from the averages brought out at the foot of the table that taking all 



