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Scientific Proceedings (131) 



been extended using dosages of sodium benzoate based on body 

 weight in one series of 21 (50 milligrams per kilo) and on body 

 surface in another series of 66 (1.8 grams per square meter of 

 body surface). Body surfaces were obtained from the height- 

 weight formula and chart of Dubois and Dubois. 2 The dosage 

 based on surface was obtained by calculation after determining 

 the body surface of one individual of average size and weight 

 who had had 50 milligrams of benzoate per kilo of body weight. 

 All individuals of both series were medical students who made 

 the tests on themselves as part of their work in Physiolical Chem- 

 istry and whose urine specimens I made check analyses on by 

 the method of Kingsbury and Swanson. 3 The benzoate was in- 

 gested quantitatively the first thing in the morning, having voided 

 the night urine immediately before. Breakfast was omitted. 

 The total water intake was 500 c.c. in every case. The urine was 

 collected for the next three hours and immediately analyzed. 

 The small and variable 3 hour normal output of hippuric acid 

 independent of the ingested benzoate is included in these figures. 

 Experience has shown that it is unnecessary to determine this 

 and correct for it in the practical application of the test. In the 

 first series of 21 it was noted that the groups of heavier indi- 

 viduals generally put out a smaller amount of hippuric acid per 

 kilo of body weight than did the groups of lighter individuals, 

 although all received the same dosage of sodium benzoate per 

 kilo of body weight. This is shown in Table 1 in the form of 

 percentages of excretion for the different weight groups. 



This indicates that the actual amount of functioning tissue 

 in the kidneys is less in its relation to body weight in the heavy 

 person than in the light. This was also shown by a fairly high, 

 but negative correlation coefficient' 0.50, between the per cent, 

 excretion and the body weight with a probably error of ±22 

 per cent. 



In a second group of 66 normal individuals given benzoate, 

 1.8 grams per square meter of body surface, it was noted that 

 the average percentage of excretion for groups of different body 

 weights was nearly constant, indicating that the actual amount 

 of functioning kidney substance is more nearly in proportion 

 to the body surface than to the body weight. Calculations have 

 shown that by using the square root of the body weight as a 



2 Dubois and Dubois, Arch. Int. Med., 1917, xvii. 



8 Kingsbury, F. B., and Swanson, W. W., J. Biol. Chcm., 1921, xlviii, 13. 



