126 PHYSIOLOGY AND NATIONAL NEEDS 



completely sterilises the wheat as regards insect life, 

 so that the weevils must be killed by this treatment 

 at all stages of their development. 



In Nos. 1 and 3 of the Eeports of the Grain Pests 

 (War) Committee of the Eoyal Society we have 

 published details of twenty-seven different experi- 

 ments of this kind, sufficient, we hope, to discredit 

 for ever the remarkable physiological powers attri- 

 buted to grain insects. 



It is worth while pausing for a few moments to 

 consider the origin of so widespread a belief. People 

 talk glibly about air-tight bottles and hermetically 

 sealed tins, and will open such bottles or tins and 

 show you live insects in them, but if you ask them 

 how they know them to be air-tight or hermetically 

 sealed you will probably either get no answer or 

 be told that some inspecting authority has passed 

 them as '' intact," which seems to mean little 

 more than that they have not been opened. We 

 have been informed by an Army Depot officer that 

 tins of army biscuits are described as " intact " 

 even if they have split seams — provided the lid has 

 not been touched; and the assumption that "in- 

 tact" and " hermetically sealed " mean one and the 

 same thing is clearly responsible for the statement 

 that the larva of the much-dreaded flour-moth — 

 Ephestia huehniella — works its ravages in hermetic- 

 ally sealed tins of army biscuits. 



A few months ago the same officer brought me 



