68 



GROWTH HORMONES IN PLANTS 



Noon 



Noon Noon 



Time in 4 hour periods 

 A 



Noon 



Noon 



Noon 



Noon 



Noon 



Time in 4 hour periods 

 B 



Fig. 20. — Auxin content of human urine. A, hourly elimination of auxin in 

 urine increases markedly following a meal, indicated by an arrow. B, auxin 

 elimination after ingestion of various foodstufTs shows a sharp rise in the case 

 of salad oil, which probably contains some crude form of the growth hormone. 

 One hundred cubic centimeters water were consumed hourly. (After Kogl, 

 19336.) 



