1900] CHANGE OF FORM IN GREEN ALG# 299 
Having shown thus the partial and total pressures of the nor- 
mal solution, I shall now describe the modifications of this solu- 
tion which I have used. Four solutions were made up according 
to the formula given above, excepting that each was deficient in 
one of the four constituent salts. All of one salt, it was thought, 
_ should not be omitted, since then, as in higher plants, patho- 
+ logical responses would probably ensue. In these solutions the 
deficient salt was reduced to one tenth its normal quantity. 
The decrease in osmotic pressure, caused in each instance by 
this diminution of one salt, was calculated by the two methods 
just spoken of, and of each of the three other salts a sufficiency 
si added to increase the pressure by an amount equal to one 
third of the calculated decrease. Two full sets of these solu- 
tions were made up and used, one by assuming dissociation com- 
plete, the other by DeVries’ method. These two solutions were 
identical in their effects upon the plant. Thus finally we have 
four solutions in each of which a deficiency of one salt is 
obtained, and the osmotic pressure of the solution is kept up to 
formal by an increase in the amounts of the other three salts. 
4 amounts are not equally increased by weight, but accord- 
. om pressure which they produce when in solution. I 
INo . these solutions as follows: A, delicies in Ca 
a ; B, deficient in KNO,; C, deficient in MgSO, ; D, 
given b 2 K,HPO,. K will denote the normal solution 3 
| a nop. The pressure will be expressed in terms of 
ad part of my work was done in a ae 
bike : upon the plants of the four solutions just describe 
is thy — one of Knop. They were all diluted, gee 
ae me to the various strengths given in table = 
: a 4. ‘ tests were made with solutions of ie). pe 2 
simple soy salts with which we have been dealing. ne 
Pressure as .. were made up so as to have the same — . 
oar € complex ones just described. They will be des 
as follows: E, a solution of Ca (NO,) 2: F of KNOs; 
Wit 
Q inated 
of : | | 
Made 9 oe H, of K,HPOQ,. Calculations for these were 
nly by De Vries’ coefficients. 
rx, 
