264 
Walter Stiles and Ingvar Jorgensen. 
Cu(N 0 3 ) 3 Concentration. 
Molecules of Ca(NO a ),. 
Molecules of Cu(NO,),. 
0008 
6-25 
0-0004 
2-50 
0-0001 
0-63 
Copper sulphate behaves quite similarly to copper nitrate. It 
is shewn that the result is not to be related to decreased ionisation 
of Cu(N 0 3 ) 2 in the mixed solution, either on account of the ordinary 
law governing ionic dissociation in a solution of two salts with a 
common ion, or by the formation of a double salt only little 
dissociated. 1 It appears that the antitoxic action must be effective 
on the spores themselves. 
Lead nitrate was found to be considerably less toxic than 
copper nitrate. Experiments were conducted in which combinations 
of Pb(N0 3 ) 2 of three distinct strengths (000016M, 0-00033M and 
000066M) with Ca(N0 3 ) 2 were tried. To obtain mainly normal 
germimation with each of these three strengths a ratio of of 
had to be used: a result in contrast to that with copper. Magnesium 
was found to be about one-fifth as effective an antidote as calcium in 
counteracting the toxicity of Pb(N0 3 )„. The same relation between 
magnesium and calcium was found in regard to counteracting the 
toxicity of Zn(N0 3 ) 2 . 
Aluminium nitrate was found to be decidedly toxic, but in no 
case did the addition of either calcium or magnesium nitrate 
produce any effect. 
Hawkins concludes that no broadly general hypothesis will 
explain the various antagonistic actions, and infers that the 
explanation of each case will have to be worked out for itself. 
There can however be no doubt whatever that it is by obtaining 
data of a quantitative nature, such as Osterhout, Hawkins, and 
particularly Sziics, have been attempting, that we may hope to 
arrive at a fuller knowledge of the meaning of antagonistic action. 2 
1 It had previously been shewn by Clark (5) that the addition of small 
quantities of sodium chloride to a solution of mercuric chloride increased the 
toxicity of the solution, but that larger quantities caused a decrease of toxicity. 
He supposed a double salt was produced with a much higher dissociation 
coefficient than that of mercuric chloride. 
2 Since this paper was written Osterhout (31) has called attention to the 
necessity of correct criteria of antagonism, and has suggested a way in which 
the amount of antagonism may be measured and numerically expressed. His 
scheme is further developed in a later paper (32), which also promises us the 
publication of the results of further researches. 
