320000 



:] 260000- 



I 



^2000001- 



I 



^ 140000 

 ^ 80000 

 20000 f- 



20 40 



60 80 

 DAYS 



100 



120 140 



-^ 9000 

 ^ 6000 [ 

 ^ 3000 ' 



§^9000 

 v^ 6000 - 

 ^ 3000 - 



5 6000 



^ 3000F ""-. 



5 6000 

 5 3000 



w 



130 150 170 190 ZIO 230 Z50 270 290 

 DAYS 



Fig. 1 8. — The excretion of gonadotropic substance(s) in the urine during preg- 

 nancy. Days are counted from the first day of the last menstrual period. The 

 termination of pregnancy is indicated by arrows. (From Browne and Venning, 

 Lancet, 231, 1 507-11 [1936].) 



