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AMERICAN BEE JOURNAL. 



obligations to Dr. Sternberg for ascer- 

 taining the thermal death point of the 

 spores of bacillus alvei, when exposed 

 to moist heat. I believe Dr. Sternberg 

 is entitled to the credit of priority in 

 determining this point. 



Dr. Sternberg says: "It will be 

 understood that the experiments included 

 in this report relate to moist heat, that is. 

 to say, the test organisms were in fluid 

 cultures, and in a moist condition. The 

 effects of dry heat (italics in both cases 

 are mine) on desiccated organisms is 

 quite another matter. This has been 

 studied by Koch and Wolffhuegel, and 

 their results have been given by Dr. Geo. 

 H. Rohe, in his essay on ' Dry Heat,' in 

 the report of the committee for 1885." 



I took the liberty of addressing a 

 letter to Prof. Rohe, explaining the 

 question under discussion, and the 

 ground I had taken, that spores in 

 melted wax are in the position of spores 

 exposed to dry heat, and asked him if 

 he could favor me with a copy of his 

 essay. He very kindly sent me the 

 Report of the Committee on Disinfect- 

 ants for 1885, containing his essay on 

 " Dry Heat," accompanied by a letter 

 from which I make the following ex- 

 tract : 



" Comparing Dr. Sternberg's observa- 

 tions upon the thermal death point of 

 micro-organisms (Public Health, XIII, 

 page 97), I find the resistance of spores 

 of bacillus alvei to be equal to that of B. 

 anthracis and B. tuberculosis, two of our 

 most resistant pathological microbes. 

 Now, Koch and Wolffhuegel showed that 

 a temperature of 248° to 262^ F. 

 failed in three hours to destroy the 

 vitality of these organisms. Hence, it 

 seems to me we may extend the same 

 observation to B. alvei. In the absence 

 of direct experiment, it seems to me that 

 your point, i. e., that the heat applied 

 in melted wax is dry heat, is well taken, 

 and I should take your contention as a 

 valid one." 



In another series of observations by 

 Koch and Wolffhuegel, it was found that 

 bacillus anthracis was killed by an 

 exposure of 3 hours and 10 minutes to 

 a temperature of 283°. As the result of 

 further observations, they say : " Com- 

 plete destruction of the spore-bearing 

 organisms did not follow, unless the 

 temperature of 282^ had been reached." 



Dr. Rohe closes his essay with the 

 following paragraph : " Koch and 

 Wolffhuegel {Mittheilungen aus dem 

 Kaiserlichen Gesundheitsarate, page 231) 

 submit the following conclusions, which 

 seem to the writer to be fully justified 



by the results of their own and other 

 observations here collected:" Among 

 the conclusions here referred to by Prof. 

 Rohe, is the following : " Bacillus spores 

 require, for their destruction in hot air, 

 a temperature of 284^ F. maintained 

 for 3 hours." 



Dr. Sternberg gives a table containing 

 the thermal death point of 37 different 

 micro-organisms, as regards moist heat. 

 The time of exposure required was from 

 4 to 10 minutes. The lowest tempera- 

 ture required was 122°, and the highest 

 2120, only five of the organisms requir- 

 ing the latter temperature for four 

 minutes, and one of these five was 

 bacillus alvei 4 showing, as Prof. Rohe 

 says, that it is one of the most resistant 

 pathogenic germs known. 



From the foregoing I think it is now 

 clear that Mr. Dadant, and others who 

 contend that a temperature of from 

 140^^^ to 2120 is sufficient to sterilize 

 wax, are mistaken. Whether an expo- 

 sure to, say, 200^ for 7 or 8 hours, 

 as in Mr. Hunt's case, is equivalent to 

 284° for 3 hours, can be only a matter of 

 conjecture in the absence of experiment. 



W^hat is required to make sterilization 

 a certainty is a tank having a jacket to 

 which steam, under pressure, can be 

 supplied, the same as is done in packing 

 houses for rendering lard. From all 

 that seems to be known at present, wax 

 kept at from 284- to 290^ for 3 hours 

 might be sent out without any qualms 

 of conscience as to its being the means 

 of spreading foul-brood. 



I purposed replying to the contention 

 that experience in using foundation 

 proves that it does not spread the 

 disease, and therefore it does not contain 

 live germs of foul-brood, and to show 

 that there is a cause for the partial 

 immunity from the spreading of the 

 disease in this way, which, up to the 

 present, does not seem to have occurred 

 to any of those who have taken issue 

 with me on this subject, but I must not 

 forget Voltaire's remark that the way to 

 be tiresome is to say everything, so for 

 the present I shall " break off." 



Lindsay, Ont. 



After putting Mr. Cornell's article in 

 type, we sent a copy, in proof, of it to 

 each of the persons who replied to his 

 former article, and here are the criti- 

 cisms : Mr. Dadant says : 



In the foregoing article, after stating, 

 regarding the report of the experiments 

 made by Dr. G. L. Sternberg, that "the 

 results of the second experiment showed 



