April, 11] discussion: FATAL TEMPERATURES 159 



to be cleaned out, and prepared for fumigation, but with this other 

 method it is not necessary to clean out the accumulations and some 

 millers state that they would rather spend S2,000 or $3,000 for heat- 

 ing apparatus than to spend $500 or $600 every year for fumigation. 



Mr. Washburn : It seems to me that this is a most excellent paper. 

 At the same time I do not see how they estimate the expense of fumigat- 

 ing at such a high figure because the material is not very expensive. 



Mr. Dean: When you use 1,500 pounds of cyanide the material 

 counts up, to say nothing of the two or three days shut down. 



Mr. Washburn: In Canada in a very large mill, we used a ton of 

 material, but even that expense would have been trebled if they had 

 to pipe the mill. Of course, if you can reach Tribolium buried two, 

 or three, or four inches in flour, you have done a good work. The 

 gas would not go through a sack of bran. 



Mr. Dean: They removed a large roll and the insects were killed in 

 the accumulation back of the machinery which was two inches thick. 



Mr. Washburn : Some millers have a wrong idea as to hydrocyanic 

 acid gas. I have run to earth four or five stories of men killed by 

 accident. One or two men have been killed by bisulfid of carbon, but 

 I have yet to find a single individual killed by hydrocyanic acid gas. 

 Several men, to my knowledge, use this once or twice a year, when 

 they clean, but they never successfully reach Tribolium, that insect is 

 so insidious, and if heat will do it, it is a good thing. 



Mr. Headlee : I cannot forbear raising the question as to whether, 

 if the mills are tight and properly heated during the summer season, 

 and all the insects killed, there would be any necessity for heating 

 during the winter. 



Mr. Lowe: The point which interested me particularly in this 

 paper presented by Mr. Dean, is the fact that the insects were killed 

 in the sealed container. I have a mill and big seed store placed at 

 my disposal, and I have been experimenting with a new product which 

 we have, but have not obtained any good results, particularly in 

 the spouts, and in the inaccessible parts, but I shall now test the 

 idea Mr. Dean has brought out and hope by our next meeting to 

 bring some corroborative results. 



Mr. Washburn: I would like to ask Mr. Dean if this method will 

 kill the eggs. 



Mr. Dean: In the experiments in the laboratory where it required 

 from 8 in the morning until 5 o'clock in the afternoon to reach the 

 high temperature, we had eggs and larvae, and the eggs perished before 

 the larvae. Eggs subjected to a temperature of 120° for fifteen min- 

 utes were killed. It takes a longer time to penetrate mill products. 



Mr. Washburn: I was thinking of the spouts, elevators, etc. 



