INORGANIC SALTS TO MONILIA SITOPHILA 275 
cases at least, salts may be more toxic in a medium that is well 
suited to the growth of Monilia than in one which is less favorable. 
TABLE VI 
THE TOXICITY OF FERRIC CHLORIDE IN SACCHAROSE, GLUCOSE, LACTOSE, STARCH, 
D PEPTONE MEDIA 
Saccharose 5% Glucose 5% | Lactose 5% | Starch 5% | ac 5% 
Tey | 
BA | Goth ee coe cae GoM, Cone Sac G.4, Gone ae oa erg 
FeCl; | 3 Days | FeCls FeCls FeCls Days; FeCls | 3 Days 
| | 
00050, -— 00050 - | .000400 | - Org. | = .050 | = 
00040; — 00040 _ .000300 - 00L2 5 |. = 045 |. — 
00030, — 00030 - 000200 _ .OOIL _ 040 | — 
00020; — | 00020 _ 000100 _ .0010 | _ 035 | + 
00070 | | 00010 + 000080 oe 0009 {| — | 030 | + 
00009; + | oooo9 | + 000060 - 0008 + | as foot 
00008; + 00008 + 000040 = as fa Ales 93 020 | + 
00007, + 00007 + 000020 — 9006...4. + se 3 ls “= 
00006 | + 00006 + 000010 + 0005 | + SOLO Vict 
mows | + | .00005 + .000008 a 0004 | aa os | + 
| | AE Ge Felsen, SAY a 
Table VI shows that ferric chloride is far more toxic than the 
alkali and the alkali earth chlorides which have been tested. 
Although iron has a place among the nutrient elements it is never- 
theless very poisonous. Of the alkali and alkali earth salts 
tested, potassium chloride is the least toxic. Iron chloride is 
least toxic of the salts of the heavy metals which have been used. 
It is very interesting to see that both potassium and iron are among 
the nutrient elements. This suggests that there may be some 
connection between toxicity and the nutrient relations of the 
elements. The effect of peptone on the poisonous action of ferric 
chloride is strikingly shown by the table. It is eight times more 
toxic in starch and ten times more toxic in lactose than in glucose 
and saccharose. In lactose it is more than three thousand times 
more toxic than in peptone. The average limit concentration in 
the different media is .007 molar. 
Copper is known to be very poisonous to many algae and fungi, 
and is widely used in the making of fungicides. I find, however, 
that the chloride is, with the exception of iron, less toxic than any 
of the other chlorides of the heavy metals that have been tested. 
As shown by Table VII, cupric chloride, like ferric chloride, is 
more toxic in lactose than in saccharose, glucose, starch or peptone. 
