FUNGOUS DISEASES OF THE HONEYBEE 37 



of the opinion that they rarely attack healthy bees. Occasionally 

 fungi differing from those found to be pathogenic by experimental 

 inoculation, have been isolated from mycelium found vegetating 

 within the digestive tract or tissues of sick bees. This would seem 

 to indicate that the fungi observed could parasitize the bees. How- 

 ever, since no one species other than those already discussed was 

 isolated more than two or three times, their pathogenic relation to 

 bees was not extensively investigated. 



The yeasts have been observed to occur with considerable con- 

 stancy within the alimentary canal of bees. The number of cells 

 present was usually small, and they were often limited to the contents 

 of the rectum, but a considerable number of cases have been observed 

 in which much of the contents of the honey stomach or of the ventri- 

 culus consisted of yeast cells. In most of these cases the cells were 

 evenly distributed within the contents, and, although buds in various 

 Stages of development were present, it could not be ascertained 

 whether growth had occurred within the bee. At one time yeast, 

 in more or less rounded hard masses of the size of wheat grains, was 

 found in the honey stomachs of more than 10 per cent of a lot of 

 sick bees collected in November, 1924, at Ann Arbor, Mich. Three 

 distinct yeasts, one of which was identified as Saccharomyces ellip- 

 soideus, were isolated from the masses of yeast cells. It was thought 

 possible that these yeasts had developed within the honey stomachs 

 of the bees and were responsible for their abnormal condition. 



A series of feedings with these yeasts and others, including Sac- 

 cTMroTwyces apicvlatus, isolated from bees failed to justify such an 

 assumption. None of the yeasts multiplied extensively within the 

 alimentary canal, and the bees were not seriously affected by the 

 presence within the digestive tract of large quantities of yeast. 

 Masses of yeast cells, such as were found within the honey stomachs, 

 did not form there within these inoculated bees. Such masses did 

 form, however, but without apparent harm, within the ventriculus of 

 bees that were heavily inoculated. In this case the yeast masses 

 were doubtless formed as a result of the sifting out of the cells from 

 the food contents of the ventriculus. Such a process could also occur 

 in nature when bees feed upon partly fermented honey. 



Yeasts have been found,, often in large numbers, in the tissues of 

 bees several days after their death. Among these, Saccharorruyces 

 amculatus and 8. ellipsoidevs were recognized. A small oval yeast 

 that was not identified was found in the thoracic muscles of about 

 50 per cent of a sample of nearly a hundred dead bees sent to the 

 bee-culture laboratory from South Carolina. The gross symptoms 

 of these infected bees resembled closely those of bees inoculated with 

 yeasts by being punctured with a needle that had been dipped into 

 a suspension of yeast cells. 



Following these observations on dead bees, it seemed desirable to 

 observe living bees to determine if yeasts are capable in nature of 

 parasitizing healthy bees by gaining entrance into their blood. 

 Although many apparently affected bees were examined, yeasts were 

 never found vegetating in the blood. 



Although it could not be determined whether or not the yeasts 

 found in the muscle tissues and blood of dead bees had been the 



