THE TOXICITY TO FUNGI OF VARIOUS OILS AND SALTS. 
31 
The toxicity of water-gas tar products is highly variable, much 
more so than commercial coal-tar products. By decreasing the 
specific gravity the toxicity rapidly increased. The writers do not 
wish it to he inferred, however, that this necessarily means that 
water-gas tar and coal-tar products will prove equally efficient under 
service conditions. The present results are merely suggestive. 
The fractionization of coal-tar creosote gives some interesting data. 
In the case of Forties annosus the three lower fractions proved con- 
siderably more toxic than the creosote itself. In the case of F. 
pinicola the four lower fractions were included. In the former case 
Fraction II gave the best results and in the latter the greater toxicity 
fell to Fractions III and IV. This indicates that the middle fractions 
are the most efficient, but to what group of substances the greater 
toxicity is due we are not yet prepared to state. The work of other 
investigators with naphthalene, which is one of the principal con- 
stituents of Fraction II, would seem at least to militate against this 
substance. 
The high-boiling carbolineums, which approach Fraction IV in 
their physical and chemical properties, likewise approach it in their 
toxic properties. 
While the higher boiling constituents proved to be less toxic than 
the lower boiling ones, their greater permanence in wood under 
service conditions may at least partially offset the lessened toxic 
efficiency. 
The poor showing made by copperized oil against both fungi indi- 
cates that adding small amounts of copper in this form to low-toxic 
petroleum or vegetable oils will produce a mixture of doubtful 
fungicidal value. 
TOXICITY TO FUNGI OF CERTAIN OF THE MORE IMPORTANT PRE- 
SERVATIVES. 
In order to bring together in convenient form for comparison the 
results secured by various investigators in the use of certain impor- 
tant preservative substances, as well as those originating in our own 
laboratory upon the preservatives mentioned, Table IV has been 
prepared, indicating the salient features of such tests. 
In making comparisons, the sources of error as well as the degree 
of refinement which the figures represent, should be fully considered. 
Table IV. — Toxicity of various preservatives to certain wood-destroying and other fungi. 
Toxic substance. 
Organism. 
Toxic point. 
Culture 
medium. 
Duration of 
test. 
Investigator. 
A.—rNOKGANIC COM- 
POUNDS. 
Ammonium chromate 
[(NH 4 ) 2 Cr0 4 ]. 
Ammonium fluorid 
Coniophora cerebella. 
do 
Per cent. 
Under 1 
Under 0.1... 
Agar 
...do 
8 to 10 days. 
do 
Falck. 
Do. 
[NH4F], neutral. 
