FUNGOUS DISEASES OP THE HONEYBEE 



29 



an extraction was made from a new set 

 chloroform had evaporated the residue 



extraction with chloroform, 

 of cultures. As soon as the 

 was taken up with water, 

 mixed with honey, and ad- 

 justed to about pH 4.6. The 

 precipitate that formed with- 

 the first addition of chloro- 

 form was treated in the 

 same way. The death rate 

 was increased when either 

 the residue left after evapo- 

 ration of the chloroform or 

 the precipitate was fed to 

 caged bees. The death rate 

 from the residue was 

 much higher than that from 

 the precipitate, which shows 

 that there is a greater 

 amount of toxin in the chlo- 

 roform. (Table 4 and fig. 

 4. ) It may be that the pres- 

 ence of the toxin with the 

 precipitate can be accounted 

 for by adsorption. 



Table 4. — Length of life of 'bees in cages when the extract from the culture 

 medium of Aspergillus fla/vus AoSc was mixed with their food 



FiGUEB 4. — Rate of mortality of honeybees at daily 

 intervals after the commencement of feeding 

 with extract of the medium in which As/p&rgMlus 

 flaivus had been cultured : 1, With chloroform 

 extract from medium made slightly basic with 

 potassium hydroxide before extracting. The 

 food containing the extract was then adjusted 

 to a concentration of about pH 4.6 with sul- 

 phuric acid just before it was given to the bees. 

 2, With the precipitate obtained upon the addi- 

 tion of chloroform to the basic medium. The 

 food containing the extract was adjusted to a 

 concentration of about pH 4.6 before it was 

 given to the bees. 3, With ether extract of the 

 medium adjusted to an acid reaction after ex- 

 tractions had been made with chloroform 



1 Records of the death rate were not made on this day. 



As checks upon the experiments, extractions were made with ether 

 and with chloroform from medium that had not been used for cul- 

 turing. These extracts were added to diluted honey and fed to bees. 

 All of this food was consumed, but none of the bees appeared to be 

 poisoned since the death rate was normal. (Table 5 and fig. 5.) 



Table 5. — Dailj/ death rate of tees in cages when gVoen honey for food 



1 Three other check lots of 25 each showed that the first deaths of normally fed bees occurred on the 

 sixth or seventh day. 

 ' Becords of the number of deaths were not made on these days. 



