76 MISSOURI BOTANICAL GARDEN BULLETIN 
long bacteriological experimentation. While a single ex- 
posure to. steam, with a temperature of approximately 
212° F., will kill most of the bacteria ordinarily found on 
vegetables, certain germs are provided with cells or spores 
which will resist the action of even a greater heat. By set- 
ting aside for 24 hours, these spores grow into a stage which 
is more easily attacked by the heat and after the second cool- 
ing period and the third steaming, the last of these more 
resistant forms are killed. 
Once all the bacteria within the jar are destroyed, it but 
remains to prevent the access of outside germs. This is 
accomplished by tightly closing or sealing the jar by the 
method provided. It is obvious that no matter how thor- 
oughly the contents of the jar may be sterilized, if the rub- 
ber rings and tops are not applied until the end of the opera- 
tion, germs from the air may be introduced which will render 
all the work done useless. 
By the method above described, practically all vegetables 
grown in the garden may be preserved indefinitely. Peas 
beans, beets, okra, squash, tomatoes, asparagus, and corn will 
all retain their characteristic flavor, and if the jars are kept 
in the dark there will be but little loss of color. If failure 
results, it will be due to a disregard of the directions given 
relative to the time of exposure to steam, or the number of 
sterilizations, or carelessness in finally sealing the = The 
term “jar” has been used throughout this article because 
glass containers are more easily cleaned and sealed, but with 
— precautions the ordinary tin can may be used as well. 
f course, the tin top should be on the can from the first. 
The type of jar with spring attachment instead of screw to 
has the advantage that after the final sterilization and cool- 
ing, before the jar is put away for the winter, the results 
of the treatment may be tested. After standing for two or 
three days, if the spring be released and the jar carefully 
picked up by the lid, the top will come off if sterilization 
has been incomplete. Bacteria within will have produced 
sufficient gas and consequent pressure to overcome the par- 
tial vacuum produced by the heating. In such cases it will 
probably be sufficient to sterilize once more, although in 
some cases if the directions given have been seriously neg- 
lected, so that the contents have obviously fermented, time 
will be saved by throwing away the contents and trying 
again. 
_- The os of time for each steaming, namely, one hour, 
is designed for pint or quart jars only, Jars of larger 
capacity, because of the greater time necessary for the steam 
