EUROPEAN FOULBROOD. 31 
SACBROOD 
Sacbrood is recognized by the death of larve after capping, by the 
saclike appearance, the watery granular consistency of the larval 
remains, and the absence of viscidity. The absence of microorgan- 
isms characterizes the microscopic picture in sacbrood. 
OTHER CONDITIONS 
Conditions referred to as chilled brood, overheated brood, and 
starved brood must be differentiated from European foulbrood. This 
can usually be done with little difficulty by a comparison of the symp- 
toms present with those of European foulbrood. The history of 
the case is of much value. Brood dying after being removed from 
the hive and before examination is made shows often an interest- 
ing similarity to European foulbrood. B. alvei and B. pluton are not 
found in these conditions. The absence of bacteria, or their presence 
in small numbers only, and a lack of uniformity of the species when 
present, characterize the bacteriological findings in these cases. 
PROGNOSIS 
There is no uniformity in the prognosis in European foulbrood. 
The diseased colony may recover completely from the infection, suf- 
fering only a slight loss in strength as a result of it; the colony may 
recover but sustain considerable loss; or it may die out entirely, as a 
result of the disease. The infection may spread only slightly to other 
colonies of the apiary or the entire apiary may become infected. The 
losses sustained vary from slight to total. The tendency for Euro- 
pean foulbrood to disappear is greater after midsummer than before. 
Whether a larva once infected ever recovers from this disease is 
not known, but the evidence at hand indicates that it may. This 
seems to be especially probable when the infection takes place during 
the latter part of the feeding period of the larva. Queen larve are 
susceptible to infection, but sufficient data are wanting from which 
to estimate the extent to which queenlessness may result from the 
disease. In experimental colonies queens have been reared in the 
presence of a considerable amount of European foulbrood infection. 
The prognosis for the colony in the case of European foulbrood 
may be said, therefore, to vary from very good to very grave, many 
recovering entirely from the infection without treatment and without 
appreciable losses, while others rapidly decline and finally die out. 
SUMMARY AND CONCLUSIONS 
The following is a brief summary of facts regarding European 
foulbrood, together with some conclusions based upon them: 
1. European foulbrood is an infectious brood disease of bees caused 
by Bacillus pluton. 
