INORGANIC SALTS TO MONILIA SITOPHILA 279 
Overton (22) has pointed out that mercuric chloride, which 
differs from most salts in being more soluble in ether, lanolin, etc., 
exerts its poisonous action more quickly than the other salts of 
the heavy metals and thinks that this fact favors the view that 
the plasma membrane is a lipoid layer about the cell. The data 
in Table XI supports the evidence for the great toxicity of this 
salt in all of the different media used. It is, however, more toxic 
in starch and less toxic in peptone than in any of the other media. 
It is two hundred times more toxic in starch than in peptone. 
It is also more toxic in lactose than in glucose or saccharose. It is, 
as noted, the most toxic of all the chlorides used, its average limit 
concentration being .o004 molar. A comparison of the limit con- 
centrations of the chlorides of zinc, cadmium and mercury shows 
that the toxicity of these salts is roughly proportional to the 
atomic weights of zinc, cadmium and mercury. Mercury is 
somewhat more toxic than would be expected from its atomic 
weight but the relation shown here suggests that a better knowl- 
edge of the toxicity of non-nutrient salts in different media may 
further support the view that toxicity is related to the periodic 
functions of the atomic weights of the elements. 
TABLE XII 
THE TOXICITY OF VARIOUS CHLORIDES IN FIVE DIFFERENT MEDIA 
V5 Vial 
lam NH] Na- 
| KCI)" ci*} cr | 
Ca- on | FeCly | CuCl, | ZnCl, | CoCly | CdCl, | HgCl, 
2 
5) 
, 
.26 | .50 | .30 /.00010 | -00090° .00040 .00009 .00060 stamina 
0020 |.00010 
feo} 
°o 
x 
° 
N 
° 
° 
° 
° 
= 
° 
>oo0¢ 
o°0 
oo 
oo 
o 
° 
i] 
° 
a] 
° 
° 
S 
Vo) 
| 
; 12 | |.0000 
.80 | .50 | .20 .00080 | .00045 |.00006 00060 |.00050 |-00001 
| .40 | .25 |.03500 |.02000 |. 01000 |.01000 |.00500 .00200 
Table XII gives the limit concentration of each salt in each 
medium used. A comparison of these values brings out some 
interesting relations. Taking the average concentrations of the 
different chlorides in the various media, we see that the alkali and 
alkali earth salts which were tested are most toxic in saccharose 
and least toxic in glucose. The heavy metals are most toxic in 
lactose and least toxic in peptone. While potassium chloride is 
Most toxic in starch and least toxic in saccharose, sodium chloride 
is least toxic in starch and glucose and most toxic in saccharose. 
