34 BULLETIN 810, U. S. DEPARTMENT OF AGEICULTURE. 



31. Robbing from diseased colonies of the apiary or from neigh- 



boring apiaries is the most likely manner in which European 

 foulbrood is transmitted in nature. 



32. Brood-combs containing diseased brood, if given to a healthy 



colony, serve as a medium for the transmission of the disease. 



33. European foulbrood is not likely to be transmitted by queens or 



drones. Whether they ever do so has not been demonstrated. 



34. As a rule a hive which has housed a European foulbrood colony 



should not be considered as a fruitful source of infection. The 

 facts indicate that often such hives could be used with im- 

 punity for housing colonies without treatment. Flaming 

 them inside certainly removes all danger. 



35. The transmission of European foulbrood by way of flowers, 



visited by bees from diseased colonies and subsequently by 

 those from healthy ones, is not to be considered as a likely 

 source of infection. Whether the water supply is ever a source 

 of danger is not known. It is evidently not a fruitful source. 



36. The disease is not likely to be transmitted through the medium of 



the clothing or hands of the apiarist. 



37. Tools and bee supplies in general do not serve as means for the 



transmission of the disease in the absence of robbing from such 

 sources. 



38. It is usually possible to diagnose European foulbrood from the 



symptoms alone. A definite diagnosis can be made from suit- 

 able samples by bacteriological methods. 



39. The prognosis in European foulbrood varies from very good to 



exceedingly grave. The tendency for a colony to recover en- 

 tirely from the disease is much greater than in American- 

 foulbrood. 



40. Considered from the technical point of view, much is yet to be 



learned concerning European foulbrood. For practical pur- 

 poses, however, it can be said that sufficient knowledge has 

 been gained to make it possible for the beekeeper to devise a 

 treatment which will be logical, efficient, and at the same time 

 economical. 



LITERATURE CITED 



(1) Bahr, Louis. 



1904. Vore bisygdomme. Foredrag holdt ved DBF's Diskussionsm0de i 

 Grejsdalen den 11. Septbr. 1904. (Efter Foredragsholderens 

 manuskript. ) Roskilde [1904] 17 p. (Saertryk af " Tidsskrif t 

 for Biavl," Nr. 16 og 17, 1904. 



(2) 



1915. Sygdomme hos Honningbien og dens Yngel. Meddelelser fra den 

 Kgl. Veterinser-og I^andboh^jskoles Serumlaboratorium, 

 XXXVII. 109 p., 11 fig. 



