44 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



flour, and a pancake flour. These flours were subjected to a heat 

 several degrees higher than that recommended for a mill. The low 

 grade hard-wheat flour was not only subjected to a temperature of 

 140° for nine hours, but the same samples were reheated to the same 

 temperature two and six weeks later to ascertain whether a second and 

 third heating of the same flour would have any injurious effect. The 

 pancake flour was subjected to a temperature of 130° for forty-eight 

 hours. The baking tests of all these experiments showed conclu- 

 sively that the heat had absolutely no deleterious effect upon the 

 baking qualities of the flours. 



Some Uncalled for Criticisms 



The objection made by some that the insurance companies will not 

 permit heat is without any foundation. The only instances of an 

 objection of this sort that has been brought to the attention of the 

 writer was in case of mills that may be equipped with the automatic 

 sprinkHng system. Mr. William Reed, secretary of the Mutual Fire 

 Prevention Bureau, representing eight of the principal millers' insur- 

 ance companies, in a recent notice to all policyholders makes the fol- 

 lowing statement: "We propose to advocate the heating systems for 

 effective fumigation against the Mediterranean flour moth, weevil^ 

 and all other mill and grain infesting insects." The objection that 

 the system is not practical because of the impossibility of heating in 

 winter is one scarcely worth considering. No one is advocating the 

 heating of a mill in winter. Any one familiar with the insect infes- 

 tation of a mill knows that if a mill is heated during the latter part of 

 the summer and all the insects killed, there will be no necessity for 

 heating during winter months. The objection that heat will injure 

 the belting, check the elevator legs and the woodwork of the bolters 

 and purifiers is without a semblance of truth. In one experiment the 

 mill was heated far above the required temperatures, some of the tem- 

 peratures going as high as 150° F., for a period of nearly thirty hours, 

 and the examination showed absolutely no injury to any part of the 

 mill or the mill machinery. 



Summary of Results 



In a mill, flour accumulates in recesses and insects breed in places 

 inaccessible to the gas or vapor of any fumigating material, but heat 

 passes through all of these obstructions and penetrates the innermost 

 recesses! Many mill insects do not yield readily to hydrocyanic acid 

 gas, but no mill insect can withstand for any length of time a tempera- 

 ture of from 118° to 122° F. The writer has fumigated many mills 



