[Vol.. 2 



474 ANNALS OF THE MISSOURI BOTANICAL GARDEN' 



growth, however, of the two cultures in the renewed medium 

 was better than that of the two in the unrenewed distilled 

 water. 



In Nos. 11-22, there was better growth of tops and roots 



TABLE IV (Series 2) 



EFFECT OF RENEWED VS. UNRENEWED DISTILLED WATER ON GROWTH OF PEAS 



(Summarized Results of Part of Table III) 



Medium 



Green wt. of tops 

 in grams 



Dry wt. of roots 

 in grams 



Distilled water renewed . . . 

 Distilled water unrenewed.! 



28.55 

 28.08 



1.131 



1.259 



in four cases where the distilled water was renewed and better 

 growth in four cases where it was not renewed. Considering 



1-4 and 



table 



tained, from which it is again evident that renewing the dis- 

 tilled water exercises no injurious influence, and the conclu- 

 sion is reinforced that an exosmosis of mineral nutrients is 

 not the fundamental basis of the injury which plants suffer 

 in distilled water. Furthermore, the difference between the 

 renewed and the unrenewed distilled water cultures was very 

 marked if the plants remained for 20 days in distilled water 

 before being changed to the full nutrient solution, the differ- 

 ence being greatly in favor of the cultures in which the 

 medium was renewed. 



Figures 1 and 2 of pi. 14 illustrate the points above men- 

 tioned. In pi. 14 fig. 2 should be noted the better growth of 

 Nos. 9 and 10 — which were in renewed distilled water for 20 

 days before transfer to full nutrient solution — as compared 

 with Nos. 7 and 8, which had remained in unrenewed distilled 

 water for the same length of time before transfer. The 

 excess of growth in No. 4 over that in No. 6 is probably to 

 be accounted for on the ground that since those cultures were 

 in distilled water but 10 days neither the renewal nor the 

 unrenewal of the medium exercised much effect. Hence the 

 greater growth of No. 4 represents an individual variation. 



At the expiration of the experimental period the following 

 conditions prevailed in series 2: while the top growth in 



