306 



SCIENCE. 



[N. S. Vol. XVIII. Xo. 453. 



NaOH, and two of acid, HCl and H,SO,. The 

 alkali solutions were w/32, w/64, n/12S and 

 ji/256. The acid solutions were w/256, 7i./512, 

 w/1,024 and n/2,048. 



The corn, which was chosen on account of 

 its rapid growth and its straight main root, 

 was soaked twenty-four hours, then put into 

 a germinator containing sphagnum and al- 

 lowed to remain forty-eight hours until the 

 main roots were about 15 cm. long. 



The tests were made in test glasses with a 

 capacity of about 60 c.c. These glasses were 

 thoroughly cleaned before using. Before 

 the tests were made with the alkali the glasses 

 were first washed with normal HCl, then with 

 normal solution of the alkali used in the test, 

 then they were washed and rinsed with water. 



through the middle of the glass while mark- 

 ing. 



The glass and seedling were then put into 

 a dark chamber at a temperature of from 20° 

 to 30° C. for twenty-four hours, after which 

 the growth or elongation was measured. Then 

 the seedling was removed, lightly washed with 

 distilled water and put into a thoroughly 

 cleaned glass with distilled water and allowed 

 to remain in the dark chamber for another 

 twenty-four hours, after which it was again 

 measured. 



The tests were started at 10 a.m. The four 

 dilutions of one solution were carried on at 

 the same time. 



The results of the experiments were as 

 follows : 



TABr.E I. Solutions of KOH. Begun Mat 21, 10 a.m.. Closed Mat 23, 10 a.m. 



then rinsed with distilled water, then with 

 some of the solution used in the test. Before 

 the tests were made with the acids the glasses 

 were cleaned by the same process except that 

 they were washed first with alkali solution 

 then with acid solution. 



The glasses were filled two thirds full of 

 the solution to be used and labeled, then the 

 seedling was taken from the germinator, care- 

 fully removing all the sphagnum; the grain 

 was wrapped in dry cotton wool and fitted 

 firmly in the top of the test glass, but not 

 touching the solution, but the main root 

 reached into the solution at least 10 cm. 

 On the outside of the glass exactly opposite 

 the tip of the root a dot was made with india 

 inlv, always holding the tip of the root in a 

 line horizontal to the eye and sighting 



We see by reference to the above table that 

 there was a decided growth at n/256 and n/128 

 solutions, and when the seedlings were put 

 into distilled water the growth was approxi- 

 mately the same. Thus it is evident that the 

 elongation of the roots was due to actual 

 growth. 



In the tests with NaOH the results were 

 similar to those of KOH, from which we 

 might conclude that the toxic action of the 

 two solutions is similar. However, the roots 

 in NaOH n/64 had an appearance more nearly 

 natural after each twenty-four hours than the 

 roots in KOH of the same dilution; which 

 suggests that the Na and K ions at this dilu- 

 tion raight have some toxic influence and 

 that of the K ions is greater than that of the 

 Na ions. 



