42 



BULLETIN 431, U. S. DEPARTMENT OF AGRICULTURE. 



A small quantity of soil is added to inoculate the suspension further. 

 This is then distributed in test tubes (fig. 33), the quantity in each tube 

 representing the virus from about 15 larvae. These suspensions are 

 allowed to remain at room temperature, shielded 

 from the light. Under these conditions fermenta- 

 tion goes on rather rapidly. 



After intervals reckoned in days colonies free 

 from the disease are inoculated, each with the 

 suspension from a single tube. Results from 

 such inoculations are given in the following table: 



Table IX. — Resistance of sacbrood virus to fermentation in a 10 

 per cent sugar solution at room temperature. 



w 



Date of inoculation. 



Period of 

 fermen- 

 tation. 



Results of inoculation. 



Sept. 9, 1915.. 

 Sept. 11, 1915. 



Do 



Sept. 13, 1915. 

 July 14, 1915.. 

 July 22, 1915.. 

 Sept, 14, 1915. 

 Sept. 22, 1915. 

 July 10, 1915.. 

 June 10, 1915. 

 July 7, 19141. 

 Aug. 27,1914. 



Do 



Do 



Do 



Do 



Days. 



244 



Sacbrood produced. 



Do. 



Do. 



Do. 

 Xo disease produced. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



Do. 



1 The results recorded for 1914 were obtained with a suspension of crushed larvse, 

 in various stages of decay, in sirup made from about equal parts water and sugar. 



From the results of experiments recorded in Table 

 IX it will be noted that the virus of sacbrood was 

 destroyed in from three to five days in the presence 

 of ferment ation in 1 per cent cane sugar (saccharose) 

 at room temperature. 



As the rapidity of fermentative processes varies 

 with the temperature present, it is natural to sup- 

 pose that the time required for the destruction of 

 the virus will vary. From experiments it is found 

 that at incubator temperature the time is slightly 

 less, and at outdoor temperature it is somewhat 

 greater than at room temperature. 



RESISTANCE OF SACBROOD VIRUS TO FERMENTATION IN DILUTED 

 HONEY AT OUTDOOR TEMPERATURE. 



Employing the egg test J as used by beekeepers in diluting honey 

 for the purpose of making vinegar, it is found that it requires about 



1 This test is applied in the following manner: Water is added to honey until an egg placed in the mixture 

 e nearly submerged, the surface remaining above the liquid being only about as large as a 10-cent piece. 



Fig. 33.— Test tube 

 bearing a cotton plug, 

 used in testing the ef- 

 fect of fermentation, 

 putrefaction, and dis- 

 infecting agents on 

 the virus of sacbrood. 

 (Original.) 



