I Vol. 2 



462 ANNALS OF THE MISSOURI BOTANICAL GARDEN 



trolytes are concerned it is a very accurate and excellent 

 method and has deservedly come into more and more general 

 use for this purpose in the fields of chemistry, physics, and 



biology. 



Koeppe ('98), for instance, determined the electrical con- 

 ductivity of water obtained from various sources and com- 

 pared his results with those of other workers. He believed 

 that distilled water has a deleterious effect which is partly 

 due to a withdrawal of salts necessary to the organism, and 

 partly to a swelling of the tissues. He was supported in his 

 views by Oldham ('09), while Winckler ('04), Kobert ('05), 

 and others argued in favor of the harmlessness of dis- 

 tilled water, especially in medical practice. Peters ('04) 

 used the electrolytic conductivity method in his work on 

 Stentor and found that there was an exosmosis of electrolytes 

 when the organism was placed in distilled water, and he 

 therefore concluded that the injurious effects noted were due 

 to an extraction of salts. True and Bartlett ('12, '15, '15 a ) 

 considered, for certain salts, not only the excretion but also 

 the absorption of electrolytes under balanced and unbalanced 

 conditions of the medium. 



In a recent paper in which a historical discussion of the 

 subject is also given, True ('14) concludes that over and 

 above any injurious effects caused by deleterious substances 

 in the distilled water there is still a ''residuum of harmful 

 action due to no known type of impurity." Because this 

 harmful action seems to be most marked in water of least 

 conductivity True believes that the withdrawal of electrolytes 

 from the root tissues best accounts for the deleterious action, 

 but that this withdrawal is "not due to the aggregate differ- 

 ence in osmotic pressure between the cells of the roots and 

 the external medium." He chose lupine seedlings for his 

 work because Frank ('88) had found them very sensitive to 

 distilled water. Schulze ('91), however, after several years 

 of experience with Lupinus luteus, claimed that distilled 

 water produced no toxic effects upon those plants. 



Both before and after the appearance of the recent con- 

 tribution by True just referred to, I carried on the investi- 



