388 BOTANICAL GAZETTE | DECEMBER 
It is of interest to note that although only very slightly 
volatile at ordinary temperatures, and doubtless less so in 
aqueous solution, mercuric chlorid is sufficiently volatile even 
in dilute aqueous solution at 28°C. to be distinctly toxic. This 
was demonstrated by placing a few drops of a very dilute solu- 
tion in the bottoms of cells containing hanging drops of pure 
beet infusion inoculated with mold spores. The germination of 
the spores was inhibited. Mycologists have frequently reported 
failure to germinate spores in cells which had been sterilized by 
rinsing in a dilute solution of HgCl,. These failures were 
doubtless due to the volatile properties of this agent together 
with its extremely deadly character. 
Hn 
Botrytis proved particularly sensitive to this agent, 65530 
proving fatal. Penicillium failed to show its usual high relative | 
LA 
4096’ 
proved fatal to Aspergillus and Sterigmatocystis. Toward bacteria 
the same concentration as 
resistance, being killed by 
it is also extremely fatal, in nutritive bouillon preventing 
Li 
70000 
the development of the splenic fever bacterium (Davenport 97, 
p. 14). The data regarding its influence on the higher plants are 
n 
fatal to Lupinus, 
6400 
meager. Kahlenberg and True (’96) found 
n 
12800 
but double the toxic value of HCl. For the molds its averag® 
value will be seen to be over 800 times that of HCl. : 
Silver nitrate, AgNO, ; 0.0125, 0.375; 0.375. Almost, ater! 
altogether, as violent a poison as mercury, silver stands with itat | 
the head of the list of toxic agents tested. Among the poison? 
for molds tested, it is comparable with mercury alone gee 
the metals, and with the chromate and. dichromate anions 8 h 
formaldehyde only among the other agents. As is the case on 
bacteria (Davenport ’97, p- 14) toward the molds silver 15 2 
quently a more violent poison than mercury. Of the five a to 
used CEdocephalum and Penicillium proved more susceptible 
while it survived in 
This is unexpectedly low, being in fact 
