1915] 



MERRILL DISTILLED WATER 493 



A plant must assuredly have food in order to thrive. The 

 more food it has stored up in its tissues, the longer it can 

 survive in a medium devoid of it. But because of the absence 

 of available food it is believed that the tissues of the plant 

 begin to become disorganized and in that condition fall a 

 ready prey to bacterial and fungous action, which may then 

 set in and play a very important part in the subsequent de- 

 composition of the tissues. 



While it may seem paradoxical to assert in one clause that 

 absence of food is the fundamental basis of the injury which 

 plants undergo in distilled water, and in the very next to say 

 that exosmosis of nutrient salts plays no role, yet the results 

 obtained have substantiated that idea. Furthermore, it is 

 essential to consider the various other factors attendant upon 

 these two conditions in order to arrive at the proper conclu- 

 sions respecting their operation. Among such factors may 

 be mentioned the decrease in conductivity after a short period 

 coincident with exosmosis from normal tissues, the relation of 

 sterilization to bacterial and fungous action, the recovery of 

 plants under different conditions, and the numerous other 

 questions already considered in the body of the article, all 

 of which lend weight to the conclusions arrived at. 



IX. Summary 



A brief historical review is given in this paper of the views 



held in regard to the cause of injury to plants in distilled 

 water. 



The methods of work are outlined. 



The experimental work is given and the results discussed, 

 especially with reference to the conclusions of other workers. 



A discussion is given of the results obtained in the experi- 

 mental work and the conclusions derived therefrom are stated. 



Some of the results obtained from the experimental work 

 may be summarized as follows : 



(a). Eenewing the distilled water of the cultures every 4 

 days was in general beneficial, as shown by increased growth 

 of both tops and roots. The plants were also able to survive 

 longer in the renewed than in the unrenewed distilled water. 



