DISEASES OF BEES 27 



the hive, and then,' even without the influence of bacteria, 

 through undernourishment and lack of warmth alone, the colony 

 can get into a wretched condition. 



This temporal coincidence of the European foul brood peak 

 with the growth and weather crisis in colonies has led to the cbvious 

 interpretation that European foul brood is merely due to insufficient 

 nourishment and insufficient warmth ; that is to say, a deficiency 

 disease. We do not deny that one can often observe cases where the 

 disease after a good honey yield or after packing and artificial 

 feeding has disappeared again. But recent years have shown us 

 with all clearness that the nature of the European foul brood is 

 not sufficiently characterized by the designation " deficiency 

 disease." We have had several excellent years since 1930 and, 

 in spite of this, the disease has spread. We have also often found 

 a very marked European foul brood infection in vigorous colonies 

 that had plenty of honey and pollen. We have not noticed that the 

 race of bee has great influence on the appearance of the disease, 

 for it is just as common with the black bee of German-speaking 

 Switzerland as with the Italian bee of the canton Tessin and the 

 hybrid bee of French-speaking Switzerland. All cur experts and 

 inspectors are now agreed that, although environmental conditions 

 play an important role in the occurrence of European foul brood, 

 we must not, however, disregard the significant part played by 

 disease bacteria. And because we now attribute a more important 

 role to infection than we have hitherto, we must also pay more 

 attention to disinfection in its control. We are convinced, that 

 failure in the control of European foul brood comes from the fact 

 that we have tried to fight it only by indirect methods instead of 

 by the direct removal of the infectious substance, as in the case 

 of American foul brood. According to our observations it is not 

 possible for the bees, even after dequeening, to remove the infectious 

 material from the hive sufficiently. For the bacilli of European 

 foul brood are not only present in the sick and dead larvae, but 

 we also find them in great numbers under the cell cappings in cells 

 which contained living and dead nymphs. It seems that the 

 bacilli get into the cell with the excrements of the larvae before 

 cocoon spinning. So we also burn the combs in the case of European 

 foul brood and the experience of recent years leads us to hope that 

 in this way we shall succeed in curbing the increase of European 

 foul brood. 



As we attribute a more important r61e to infection the great 

 importance of bacteriological research becomes evident. We all know 

 how involved the bacteriology of European foul brood is and what 

 conflicting opinions the specialists hold to-day. However, I shall 

 not enter further into such details here and only give expression 

 to the great pleasure which it has afforded me to take a glimpse 

 at the excellent and very important research of my colleague, 

 Dr. Tarr. 



