598 The Philippine Journal of Science mo 
salts in the following partial volume-molecular concentrations: 
0.0052 M calcium nitrate, 0.0180 M monopotassium phosphate, 
and 0.0150 M magnesium sulphate. The two solutions differ 
in the value of the Mg/Ca-ratio, which in Shive’s solution has 
a value of 2.88, while in the four-salt solution with chlorine it has 
a value of only 1.72. As would be expected from this difference 
in the Mg/Ca-ratios, magnesium injury was less pronounced 
in the four-salt solution than in Shive’s best solution. The best 
solution with chloride for tops has quite different salt propor- 
tions from Tottingham’s best four-salt solution without chloride, 
which has potassium nitrate instead of potassium chloride and 
has a higher partial concentration of calcium nitrate. 
The four salts used by Tottingham (potassium nitrate, mag- 
nesium sulphate, calcium nitrate, and monopotassium phosphate) 
are the same as are employed in the solution generally called 
Knop’s solution, and the three salts used by Shive (magnesium 
sulphate, calcium nitrate, and monopotassium phosphate) are 
those used in the Birner and Lucanus solution. Likewise, the 
four salts used in the present study are the same as those of the 
solution that has come to be known as Detmer’s, which contains 
the four salts in the following volume-molecular proportions: 
0.0130 M calcium nitrate, 0.0039 M monopotassium phosphate, 
0.0044 M magnesium sulphate, and 0.0072 M potassium chloride. 
In the case of each of the three solutions, it has been found that 
the well-known solution could be markedly improved for the 
growth of wheat by altering the salt proportions. As indicated 
in the present study, Detmer’s solution may be expected to give 
only about 0.80 as high top yields as does solution T2R4C2. It is 
important to note that at least thirty out of the eighty-four 
different sets of salt proportions employed in the first series of 
this study gave higher yields than the one indicated for the 
Detmer proportions. 
It is worthy of particular attention that, with an osmotic value 
of 1.60 atmospheres or higher, the Shive three-salt mixture pro- 
duced magnesium injury when the salt proportions were such 
as to give the highest yield of tops. This was also true of the 
four-salt mixture of the present study in the first series ; but the 
solution giving highest top yields did not exhibit this injury in 
the second series. It has been suggested that increased growth 
is the first response to agents or circumstances which would 
prove injuriously toxic in greater concentration or on longer 
exposure ; in other words, that slight poisoning, such as is caused 
