236 



N. W. Shock 



results in a marked increase in effective renal plasma flow. In 

 order to assess age changes in the ability of the renal vascular 

 bed to dilate, glomerular filtration rate and renal plasma flow 



80 



70 



E 



K. 60 



w 50 



40 



30 



20 



.. »• 



20 



30 



40 



50 60 



Age years 



70 



80 



90 



Fig. 8. Stroke output per sq. m. surface area versus age. Each point 



represents the average of two measurements in 49 subjects, of three 



measurements in four subjects, and a single measurement in 14 subjects. 



The hne indicates the simple linear regression for the data. 



(From: Brandfonbrener, Landowne and Shock, 1955). 



were measured in young, middle-aged, and old subjects 

 following the intravenous administration of 50,000,000 

 killed typhoid organisms (0 • 5 ml. typhoid-paratyphoid A and 

 B vaccine). The results of these experiments, based on the 



