120 BOTANICAL GAZETTE [avcust | 
As can be seen from the following table and also from jig. 4, the results 
fully confirm those above given; and though the absolute amounts 
are different, the results are relatively the same. 
It may be of interest to note here that B. subtilis from a 24-hour 
peptone agar slope was examined in hanging drops of molecular solu- 
tions of magnesium chlorid and calcium chlorid, and the organisms 
showed no perceptible ill effects from the action of the solution. The 
ciliary movements appeared normal even after 24 hours in the hang- 
ing drop. It was noticed, however, that there was little or no division 
during the 24 hours and it is likely that the calcium and magnesium 
salts exercise their toxic effects, partly at least, by inhibiting reproduc- 
tion, since the ciliary movements seemed to go on without interrup- 
tion. These remarks, however, are based on too meager experimental 
evidence to be anything else than conjecture at present, but they 
serve to indicate a field of most interesting research. 
Though they are not analogous to the lack of antagonism between 
Ca and Mg shown above, it is interesting to note two cases on record, 
in which the addition of one salt to another made a combination more 
toxic than either. One case is that cited above from OsTWALD’S 
experiments on the freshwater Gammarus, in which a combination 
of MgCl, and NaCl in solution was more toxic to that animal than 
either of these in solution alone. The other case is that noted in the 
experiments of Kr6énic and Paut (2), who found that the value of 
mercuric sulfate, acetate, and nitrate as disinfectants was enhanced 
by the addition of small amounts of the chlorids of the alkalies (K 
and Na); but, on the other hand, that the addition of the same chlorids 
to HgCl, reduced considerably the disinfecting powers of the latter. 
The first instance is not analogous to the results of the writer, 
because one of the salts used was different, and the experiment was 
carried out under conditions so totally different that the value of @ 
comparison is doubtful. In the second instance, as KRONnIG and PAUL 
themselves suggest in the same article, the increase of toxicity is not 
necessarily owing to a lack of antagonism between the two salts, 
but rather to the formation of complex double salts of mercury; 
which are characteristic of that element, and therefore this agai? 
cannot be prennetet with the tack of antagonism between Ca and 
Mg above noted. 
