214 Journal of Agricultural Research voi. xxvu no. 4 
EFFECT OF PREVIOUS TREATMENT OF SEEDLINGS ON CHANGES IN 
REACTION OF ACID SOLUTION 
The behavior of seedlings which had been grown previously in a 
complete nutrient solution, as compared with that of seedlings which 
had previously been grown in incomplete nutrient solutions, defective 
in chlorin, nitrogen, sulphur, and phosphorus, was studied. For 
instance, the seedlings which were to be grown in a solution of hydro¬ 
chloric acid were first grown in a nutrient solution which was lacking in 
chlorin. 
The nutrient solution used was diluted five times. The defective 
solutions were made up so that they differed as little as possible from the 
complete solution, except for the missing element. The seedlings were 
divided into two series: One series was grown for five days in the com¬ 
plete nutrient solution, and the other in the defective solutions. All 
seedlings were then grown for a day in distilled water and finally trans¬ 
ferred to the acid solutions with an initial reaction of P H 4. After the 
changes for two successive days had been recorded the acid solutions 
were renewed and the changes in P H values were again recorded after 
a one-day and after a three-day contact. All seedlings were then trans¬ 
ferred to the complete nutrient solutions diluted 10 times. Here they 
grew for two days, after which they were transferred to the complete 
and defective nutrient solutions, diluted 10 times. Two days later they 
were transferred to the acid solution with the initial reaction of P n 3.6, 
in which they were kept for three days, when the changes in reaction 
were again recorded. 
Table IV. — Effect of complete and incomplete nutrient solutions in which seedlings had 
been previously grown on the changes produced in inorganic acid solutions a 
Acid. 
Previous condition of 
solution. 
Reaction. 
After 1 
day. 
j 
After 2 
days. 6 
P H' 
4. 90 
4. 70 
5. IO 
4. 70 
5 - 40 
4 - 95 
5*50 
4. 80 
After 3 
days c 
( i-day 
contact). 
After 5 
days 
(3-day 
contact). 
Aiter 12 
days 
(3-day 
contact). 
Hydrochloric. 
Nitric. 
Sulphuric. 
Phosphoric. 
/ Complete. 
(Complete—Cl. 
/Complete. 
/Complete. 
(Complete — S. 
/Complete. 
(Complete — P. 
1 
! 
4 - 05 
4. 60 
4. 60 
4 - 55 
4- 65 
4- 65 
4 - 7 ° 
4. 60 | 
P H- 
4 - 45 
4 . 50 
4 - 5 ° 
4. 60 
4-45 
4 - 5 ° 
4. 60 
4- 65 
1 
P H- 
4 . 85 
4- 65 
4- 85 
4. 70 
4-85 
4- 65 
5 - IS 
4. 70 
! 
P H‘ 
4 - 25 
3 - 95 
3 - 95 
3 - 85 
4. 00 
3 * 9 ° 
5. 20 
4. 00 
a Initial Ph 4.0; number of seedlings, 15. 
& Solutions renewed after these readings were obtained. 
c All seedlings were held in complete (1:10) solution for 2 days, then for 2 days in complete and defective 
(1:10), and were then transferred back to acid solutions.with an initial reaction of Ph 3.6. 
The results (Table IV) show that the previous growth of the seedlings 
in a complete nutrient solution did not affect their activity, so far as 
their ability to lower the initial hydrogen-ion concentration was con¬ 
cerned. The previous growth of the seedlings in defective solutions, for 
the purpose of creating an avidity for the elements of the acids with 
which they were subsequently to be brought in contact, resulted, con¬ 
trary to expectation, in a depressed activity with reference to changes 
