263 
Absorption of Salts by Plants. 
the actual time taken for death to supervene. In order to determine 
whether cells were alive or dead the filaments were centrifuged. If 
the cells are alive the chloroplasts are removed on centrifuging; if 
dead the plasma and chloroplasts remain fixed. 
By this method it was shown that the poisoning effect of 
quinine hydrochloride was reduced in the presence of KN0 3 : the 
depoisoning effect is much more marked with Ca(N0 3 ) 2 . In both 
these cases there is a definite ratio of alkaloid and metal which 
gives a maximum depoisoning effect, as above a certain concentration 
the metallic ions themselves become toxic. With A1(N0 3 ) 3 the 
depoisoning action is greatest, so that Sziics concludes that the 
depoisoning effect is a function of the kation valency. The same 
was found to be the case when methyl violet was used in place 
of quinine hydrochloride. 
As the entrance of quinine hydrochloride or methyl violet into 
the cell is easily observed microchemically, Sziics was able to show 
that the depoisoning effect is actually due to the hindrance of the 
entrance of the poison. And so the toxicity of pipiridin, the entrance 
of which is not hindered by the presence of inorganic electrolytes, 
is increased rather than diminished when these latter are present. 
Finally we would call attention to a recent paper by Hawkins 
(11) in which are recorded the results of a careful investigation of 
the influence of calcium, magnesium and potassium nitrates upon 
the toxicity of copper and other heavy metals in respect to the 
germination of fungus spores. The spores used were the conidial 
stage of Glomerella cingulata (Stonem.) S and v.S. It requires a 
considerably high concentration of nitrate of calcium (about 0-65M), 
magnesium (about 055M), or potassium (above 0’9M), to inhibit the 
germination of the spores, whereas a very low concentration of 
copper nitrate is sufficient for this (about O’OOOOBM). With a 
slightly lower concentration of copper nitrate (0 , 00004M) local 
swellings of the spore wall and swollen tubes were frequent. 
Solutions of different strengths of copper nitrate (0-008M ; 
0-0004M ; O’OOOIM) were combined with calcium nitrate, and the 
strength of the latter determined, such that the mixed solution 
should produce the same result on germination as (M)0004M pure 
copper nitrate. It was found that the weaker the copper nitrate 
solution used the relatively smaller amount of calcium nitrate was 
necessary. 1 Thus for the different strengths of copper nitrate the 
following relative numbers of molecules of calcium nitrate were 
required:— 
1 Cf. Loeb’s results with Fnndulus, 
