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358
ing conditions obtained as a result of varying one salt in a food-
solution. Judging by all previous experience the general aspect
of the curve should not have altered if the second experiment had
been carried out under exactly the same condilions as the first one.
(CL, specially with regard to one or many plants in each jar,
PFEIFFER 1921, [20] p. 1—2.) Even should MITSCHERLICH’S theory
of a constant "Wirkungswert" for each food-substance not be
applicable here, it has been stated neither by RiPPEL (1922, [23 ]),
nor by Harper (1921, [10]), that the curve could not be approxi-
mated to the logarithmical form, even if the constants of the
equation vary with the different conditions. Thus, in any case,
we may consider the fact established that the curve, exactly cor-
responding to the curve of the first experiment, must have had
the same general aspect as the curve in figure 6, declining steadily
from I to VI and approximately of logarithmic shape. The author
is of the opinion therefore that none of the conclusions arrived
at above need be altered on account of any consequences of the
possibility that the experiments were not comparable, as it is only
this general aspect of the curve which has been taken into con-
sideralion in reaching these conclusions.
The only investigations on antagonism carried out with very
dilute solutions are, so far as is known to the author, those made
by Reep and BREAZEALE (1918, [21] and Reep and Haas (1923,
[22]. The latter paper came into the author’s hands after the
above-mentioned conclusions had been reached. In the first paper
the summarized conclusion states that antagonism does exist in di-
lute solutions, the molecular ratio, Ca: Na = 2: 98, (corresponding by
weight to 3.5: 96.5), being optimal for wheat seedlings (1918, [21] p.
379—380); in the second paper we find in the summary the follow-
ing statement: “The varieties of citrus here studied are known
lo possess a marked capacity for the absorption of calcium ions.
Hence in very dilute solution the amounts present may be too far
below the equilibrium point within the plant to avoid a condition
of starvation. In such cases we are dealing with the phenomenon
of starvation, rather than that of antagonism. These experiments
with citrus seedlings have not demonstrated the existence of an-
tagonism between sodium and caleium, when plants are grown
in very dilute solutions.“ (1923, [22] p. 757). In the first paper
two experiments are recorded. From the first of them it was seen,
according to the conclusions set forth in the paper (p. 376—377)
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