826 EXPEEIMENT STATION EECOKD. 



pis. Jf, figs. 4; Amer. Jour. Pharm., 87 {1915), No. 12, pp. 549-555; 88 (1916), 

 Nos. 1, pp. 12-22; 2, pp. 71-82, figs. 3; 4, pp. 156-164, fig. i).— Briefly reviewing 

 related contributions, tlie author outlines his own work with Pisum sativum 

 and Vicia faba. 



Renewing the distilled water every four days increased the growth of the 

 top and roots, lengthened the life of the plants, and continued growth longer 

 after they were placed in a full nutrient solution. The period between 5 and 

 10 days in distilled water appears to be a critical one for these plants as 

 regards complete recovery in a full nutrient solution. Sterilizing the distilled 

 water every four days by boiling for i hour favored continued growth. Greater 

 total exosmosis was obtained in the renewed than in the unrenewed distilled 

 water. 



Normal plants grown for some time in a full nutrient medium and then 

 transferred to distilled water exhibited at first greater excretion than absorp- 

 tion of electrolytes, but after a day or two absorption was in excess and con- 

 ductivity declined, sometimes for a considerable period of time. The conduc- 

 tivity curve of the full nutrient solution fell for about the first 15 days of 

 growth therein to a horizontal which was maintained for about 50 days. The 

 growth curve was in general opposite to that of conductivity. Exceptional 

 features are also noted. Greater deterioration of the roots in distilled water 

 occurred if the plants had not previously l)een grown in full nutrient solution. 



The conclusion is thought to be justified that pure distilled water is not of 

 itself toxic or injurious to plants, and that various other factors must aid in 

 causing the deterioration observed in this connection. The author inclines to 

 the view that, while exosmosis of food materials or nutrient salts is not 

 responsible for the injury observetl, the question of food relations does play 

 an important part in the incipiency of the trouble, this being quickly followed 

 by factors initiated as a result of the inimical food or nutrient relation. It Is 

 thought possible that in the absence of available food the tissues of the plant 

 begin to disorganize and thus fall a ready prey to fungus and bacterial action, 

 which continues and extends the injurious effects. 



A bibliography i.s given. 



Electrolytic determination of exosmosis from the roots of plants subjected 

 to the o.ction of various ag'ents, M. C. Mkkkii,i, (Ann. Mis.'<ouii Bot. Gard., 2 

 (191t), No. S, pp. 507-572, figs. 18). — In this paper are given the results of 

 studies on the effects of agencies wliich are considered as actively injurious, as 

 distinguished from the operation of the agencies considered in the paper above 

 noted. An attempt wjxs also made to determine the approximate boundary 

 between normal and abnormal exosmosis. 



It was found that pea seedlings grew better in distilled water in which 

 exosmosis from previously treated plants of the first crop had occurred than 

 in fresh distilled water or in that in which untreate<l plants had been grown. 

 Peas or horse beans grew better in fresh distilled water than in distilled 

 water in which seedlings had already grown for 21 days. 



Abundant exosmosis may occur from treated plants, the roots remaining 

 normal in appearance. Anesthetic vapors cause markwl exosmosis after long 

 exposure, the order of greatest effectiveness being chloroform, illuminating 

 gas, and ether. The time limits for the exposure to extremes of temperature 

 in relation to exosmosis were determined, and comparison was made between 

 the effect of dry and that of moist heat. The exosmosis curves were found for 

 various organic compounds, which, at the concentrations used, produced marked 

 excretion, and the effects of salts, singly and in pairs and with anesthetics in 

 solution, were ascertained. Antagonistic relations were not discovered in the 

 course of this work. 



