132 
Journal of Agricultural Research voi. xxvm, no. 2 
was at first erroneously called “black brood,” to distinguish it from the “foul- 
brood” of sealed larvae. “Black brood” assumed epidemic proportions in New 
York State by 1897. This gave rise in American beekeeping literature to descrip¬ 
tions of two distinct diseases, as far as the age of the larvae attacked and the 
appearance from the resulting decomposition were concerned. 
RESULTING DETERMINATION OF ETIOLOGY 
As a result of the increasing devastation by this new disease, work was started 
in New York State in 1902 (S3), which was later carried on by White (49, 60), 
on the bacteriology of these brood diseases, by which doubt was cast upon 
Bacillus alvei being the cause of any disease, although it was found to be asso¬ 
ciated only with European foulbrood. Furthermore, a new spore-forming 
bacillus distinct from Bacillus alvei was observed and cultivated on special 
culture media from the disease attacking the sealed larvae. This organism was 
at first designated Bacillus X but was later named Bacillus larvae (figs. 1 and 2). 
Subsequently this was found to be the cause of American foulbrood by experi¬ 
mental inoculation of healthy colonies with pure cultures (61). The symptoms 
Fig. 1.—Spores of Bacillus larvae. Fig. 2.—-Vegetative rod form of Bacillus larvae. 
(McCray (31)) (White (55)) 
were accurately described and differentiated by Phillips (37), definite new names 
being used for the first time in order to eliminate confusion, as follows: Ameri¬ 
can foulbrood, formerly known as “foulbrood” (“Usually the larvae are attacked 
at about the time of capping, and most of the cells containing infected larvae 
are capped”); and European foulbrood, originally called “black brood” (“This 
disease attacks the larvae earlier than does American foulbrood, and a com¬ 
paratively small percentage of diseased brood is ever capped”). 
Maassen (27) in Germany described at about the same time what is now ac¬ 
cepted as the same organism as Bacillus larvae, a spore-forming organism con¬ 
stantly found to be present in the diseased brood dying after sealing, “ Nymphen- 
seuche.” He gave the name Bacillus brandenburgiensis to this organism. Bum 
(12) in Switzerland also recognized the fact that the spores present in large 
numbers in scales in the “nymph” disease were a new species that was difficult 
of cultivation. 
White (62) later showed conclusively that Bacillus alvei is not the cause of 
European foulbrood but is only one of several secondary invaders. He demon¬ 
strated that the probable cause of European foulbrood is a nonspore-forming 
organism which he called Bacillus pluton. This organism develops before the 
