1896 | TOXIC EFFECT OF ACIDS AND SALTS UPON PLANTS 131 
growth was considerable for the first twenty-four hours, with 
generally an increase in the amount of growth for the next 
twenty-four hours. A glance at the following table will also show 
that the growth in the ,N, and ,,, solutions was somewhat 
less than in the ,,N,, solution, so that even if the growth was 
not inhibited in the former a very perceptible retardation of 
the growth occurred. Since growth was not entirely inhibited 
in the solutions from ,8,, upward, seedlings were placed in two 
stronger solutions, ,N, and ;,N,. In the ,¥, solution no growth 
whatever occurred, and at the end of the first twenty-four hours 
the roots were very soft and flabby near the tip. In the y%, 
solution, however, the roots showed quite an increase in length for 
the first twenty-four hours but for the second twenty-four hours 
showed no increase, so that the ,%, solution is the strength at 
which the roots were killed. 
ZEA MAIS. 
N 
as 00 1e00 3e00 eto 0 12800 
eee er io 
Hcl J Ist 24 hours ree a5 mm $.25"% ti.s mm $1.25" 
d 24 NOUS os ae ae 18 25 16 “ 15.25 ts 
H,SO x Ist 24 hours 2.75 Og 12.5 “ LES “ 17.5 ‘“ 
: 24 hours 27.5 < “ec 33 
HNO Ist 24 hours 4.5 66 7 “ 14 “ 16 os 
3 2d 24 hours ‘.* 9 ‘ 11.5 «“ 29 “ 
HBr P Ist 24 hours 3 “ 4 5 6 2 a 15 “ 
2d Ma OUTRO x 25 “ 13.75 “ 30.5 “ 
fo AS aamemanereumestgnsscee 
A glance at the table for Piswm sativum shows a very con- 
siderable difference in the amount of the acids which the seed- 
lings could withstand. In the case of Pisum sativum the gio 
Solution was of sufficient strength to inhibit the growth, while 
in the case of the Zea Mais seedlings it required a axya solution, 
°F a solution four times as concentrated. This very great differ- 
ence in the degree of irritability is the more worthy of note, 
since the one, Piswm, has its reserve food supply stored in the 
form of carbohydrates, while corn contains quite a large amount 
of fatty material. 
