5 1 8 Reed . — The Value of Certain Nutritive Elements 
mata were profusely branched, and showed evidence of rapid growth. The 
cells were filled with bright green chlorophyll bodies which contained 
starch. The spores in the solution in which sodium had been substituted 
for potassium had germinated, but none of the protonemata had grown to 
a length exceeding twice the diameter of the original spore. Starch could 
not be demonstrated. In solutions where no other metal of the alkali group 
had been substituted for potassium, 1 none of the spores had germinated, 
nor even shown the characteristic green colour which precedes germination. 
Two months after setting up the cultures, the results were found to 
bear practically the same relations to each other. The protonemata in the 
complete nutrient solutions had made excellent growth. The cultures in 
which sodium had been substituted for potassium showed a great many 
spores which had germinated, and produced moderately well developed 
protonemata. The protonemata in this solution had a very characteristic 
appearance, owing to the fact that most of the individual cells were short 
and swollen, giving the filaments a moniliform appearance (see figure i). 
The lack of potassium did not appear to be detrimental to the development 
of chlorophyll, but I was unable to demonstrate the presence of starch in 
any of the chloroplastids. 
The outcome of these experiments seems to indicate quite clearly that 
although potassium is absolutely essential for the proper functioning of all 
the processes of metabolism in the cell, there are certain processes which 
may go on when potassium is present in sub-minimal amounts, provided that 
sodium is also present The germination and partial development of the 
moss sporelings illustrates this principle. When no sodium was supplied 
it was found that there was still less growth than where sodium was substi- 
tuted for potassium. Further illustrations of this principle are shown by 
the work of Breazeale (’06) upon the higher plants. Another indication 
that the sodium is of some value is shown by the work of Becquerel (’04), 
who found that spores of Hypnum velutinum would germinate and grow 
for a time upon nutrient solutions containing no potassium salts. That 
there are some biological factors which play a part in this problem, is 
1 The solution in which sodium was substituted for potassium had the following composition : — 
Sodium nitrate P-5 g. 
Sodium dihydrogen phosphate . . o- 2 g. 
Magnesium sulphate 0.2 g. 
Calcium chloride o-i g. 
Ferric chloride trace 
Distilled water 1,000 cc. 
The solution in which neither sodium nor potassium were furnished had the composition : — 
Ammonium nitrate 0-5 g. 
Diammonium hydrogen phosphate . 0-2 g. 
Magnesium sulphate 0-2 g. 
Calcium chloride o-i g. 
Ferric chloride trace 
Distilled water 1 ,000 cc. 
