hog] TOXIC EFFECT OF DELETERIOUS AGENTS 293 
| eggs, after which it was boiled, strained, filtered, and poured 
into flasks. After thorough sterilization the infusion was ready 
loruse. In order to get the greatest possible uniformity it was 
found desirable to make up four or five liters at atime. In this 
medium the spores of all the forms used germinated quite uni- 
_ formly in from 3 to 8 hours (according to the species), grew 
_fpidly, and fruited normally (except Botrytis) in from 18 to 
- hours at a temperature of 28°C. 
Method of culture —The van Tieghem hanging-drop culture 
: was found to be entirely satisfactory. The cylinder part, which 
_ Woof glass, had an internal diameter of 17.5™™, and a height of 
— to, This cell, with a capacity of over 2.5 cubic centimeters, 
mrovided an abundance of oxygen for the normal development of 
the fungi. The cylinders were cemented to the slip by means 
of beeswax, and the cell was completed by sealing the cover to 
the top of the cylinder by means of a ring of vaseline, applied 
ty inverting it on a glass slip covered by a thin layer of melted 
| Wseline. A small nick was made in this ring so that when the 
_ twas applied a minute opening might be left through which 
_ He expanding air could pass when the cultures were placed in 
og thermostat. An hour later they were carefully examined, 
such as had not already become hermetically sealed were 
made so by tapping with a pencil over the tiny opening 
“erred to above. This precaution prevents much trouble and 
When culturing with volatile substances. For convenience 
dling and €xamining under the microscope two cells were 
_ on each slip. The cells were permanently labeled by 
: ing lettered and numbered labels to the ends of the slips. 
Precaution against accidents duplicate cultures were not 
os on the same slip. , 
hg ae Cover. Four or five drops of the same solution were 
SM in the bottom of the cell. The spores of the fungus to 
