GRAIN CONSERVATION 125 



scientifically accurate experiments whicli left no 

 loophole for argument. Improbable as it might 

 seem to a physiologist that any ordinary insect 

 could exist for any considerable length of time in an 

 atmosphere devoid or almost devoid of oxygen gas, 

 yet the contrary belief with regard to these weevils 

 was widely spread, and it had to be got rid of. 



Fortunately this was a very simple matter. It is 

 only necessary to seal up grain containing live in- 

 sects in glass jars or cylinders with suitable stoppers, 

 fixed on with paraffin wax, in order to convince 

 oneself that no insect can withstand such treatment. 

 The experiment has been tried repeatedly in my 

 laboratory, under various conditions of temperature 

 and moisture and with nine different species of grain 

 insects, including the two weevils. It was also 

 tried with mites. Not only do all species succumb 

 to such treatment sooner or later, but, unless a 

 relatively very large air-space be present, they do 

 so in a remarkably short time — as soon, in fact, as 

 nearly all the oxygen present has been replaced by 

 carbon dioxide. The actual time required to effect 

 this depends upon the proportion between the 

 number of insects, the amount of grain and the 

 volume of air present at the commencement of the 

 experiment, as well as upon temperature and 

 moisture. 



I may add that we have proved beyond question 

 that the hermetical sealing of badly infected grain 



