1899] TOXIC EFFECT OF DELETERIOUS AGENIS 391 
both these anions are strongly toxic, oa K,Cr,O, being fatal 
to Spirogyra in a few hours. : 
Hydrogen peroxid, H,O,; 38, 205, 127. This agent had 
an effect on the molds very similar to that described for the 
chromates. With it, however, the characteristics given for the 
chromates were somewhat intensified. Germination was but 
slightly retarded in most forms in ar concentration, and 
(Edocephalum actually showed a higher percentage germinated 
in these cultures at four hours than in the checks. The differ- 
ence, however, was not sufficient to establish the conclusion that 
the H,O, accelerated germination. That this concentration 
accelerated early mycelial growth with this form was undoubtedly 
established. At four hours the average length of the germ tubes 
i : . . . 
in aa concentration was 120“ as compared with 4op in the 
checks. At seven hours they were 3104 and 115m respectively. 
: . 
156° the limiting culture for this form, made the best mycelial 
development and matured the heaviest crop of conidia in the set. 
The characteristic already mentioned for the chromates regard- 
ing fruiting in the cultures was even more marked with this agent. 
Every culture that produced even the scantiest mycelium pres- 
ently developed at least two or three all but normal conidiophores. 
In regard to the action of this agent on other organisms, 
the data are meager and conflicting. Miquel (’83) places it third 
ss disinfecting properties of all agents used by him. In his 
results it is rated above both HgCl, and AgNOs, being agian 
antiseptic in dilution of 1 part to 20,000. This is certainly too 
igh an estimate. Sternberg (’92) found it to have a com- 
_ Paratively low toxic value for bacteria. One in 1000 kills ordi- 
nary water bacteria, cholera, and typhoid (Altehofer ’90). This 
Would be about —, or a 3 to 4 per cent. solution of the ordi- 
‘Naty Io-volume commercial article. It will be seen that this 
: n 
agrees fairly closely with its toxic properties for the molds, =) 
