586 Transactions of the Society/. 



twenty by spores, but only three of the latter and none of the former 

 contracted the disease. The general appearance of the tissues of 

 the dead fly larvae much resembled that of bees similarly affected. 



Striving to prove irrefragably the accuracy of the etiology I 

 have given, I took a number of well-developed drone larvae from 

 a healthy stock, and expressed their juices into two test-tubes 3 in. 

 long and 1/2 in. wide. No. 1 now received a very minute quantity 

 of coffee-coloured matter containing spores, whilst No. 2 was in- 

 fected with a trace of a bacillus-containing fluid from a larva just 

 dead or dying. These tubes were each supported by a simple ar- 

 rangement between the combs of a stock of bees, so that the tempe- 

 rature for germination should be kept up. In twenty-two hours, 

 examining No. 1, I found no spores, but that bacilK, mostly in 

 threads, existed in considerable numbers, whilst the bacilli added 

 to No. 2 were increasing by division, proving again that the spores 

 produce bacilli so soon as they pass into condition for germination, 

 the reverse process obtaining when these conditions cease. 



The somewhat extensive literature of this disease had always 

 gone on the assumption that it affected larvae, but larvae only. 

 This position did not appear to me to agree with many facts I had 

 observed ; e. g. we may take away two or three combs containing 

 5000 larvae each from a stock, and it will continue to progress 

 pretty much as though it had lost nothing, while if foul brood 

 attacks it and kills say 1000 of its grubs, it as a rule very per- 

 ceptibly diminishes in strength. The only theory that appeared to 

 me as satisfactory was that the adults of the hive die with the disease, 

 but that according to a necessary instinct they leave the hive and 

 finish their course alone. Going to the diseased stock then in my 

 possession, I noticed on the ground and close to its entrance one 

 bee nearly dead on its back, another hopping in abortive flights of 

 3 or 4 inches, and presently found a third and fourth worn out and 

 too far gone to enter the hive again. The first bee presented 

 nothing remarkable, but the second was almost an empty shell, the 

 air-sacs occupying nearly the whole of the abdomen. The stomach 

 and colon were exceedingly small, and the amount of fluid I could 

 obtain truly microscopic ; but this was full of active bacilli of the 

 same size and character I had previously discovered in the larvae. 

 The third and fourth bees were in similar condition. 



The consequences flowing from this discovery have more to do 

 with practical apiculture than with general science, and so here I 

 content myself with saying that bee-dealers who had in ignorance 

 of the facts always proclaimed that swarms were incapable of being 

 affected by it, and that queens constantly passing from one owner 

 to another could never communicate it, were now to be told that 

 this error had in all probability been the reason why foul brood 

 had grown to be a veritable pest, and that large apiaries were in 



