FOUL BROOD 
377 
Heavy sacbrood infection, showing a number of different stages of decay of larvae. Eggs, young larvae 
in different stages of development, and diseased larvae in same area. Natural size. — From Bulletin 431, 
Department of Agriculture, Washington, D. C. 
erally in the sealed ones. The- dead larvae, 
says Dr. White in Circular No. 169, Bu¬ 
reau of Entomology, are “almost always 
extended lengthwise in the cells, and lying 
with the dorsal side against the lower wall. 
The form of the larvae dead of 
this disease changes much less than it does 
in foul brood. The body wall is not easily 
broken, as a rule, and on this account often 
the entire larvae can be removed from the 
cell intact.” . . . “When removed 
they have the appearance of a small closed 
sac. This suggests the name of sacbrood.” 
CAUSE OF SACBROOD. 
So far no microbe or fungus has been 
discovered as the cause of the disease. 
Whatever it is, it is so very small that it 
will pass thru a Berkfield filter. Sick and 
dead larvas of sacbrood have been macer¬ 
ated and diluted with sterile water. The 
product was then passed thru a Berkfield 
filter; but it was found that the filtrate 
would again give the disease to other colo¬ 
nies. It is evident that the disease is infec¬ 
tious. Dr. White concludes that “sacbrood 
is an infectious disease of the brood of 
bees caused by an infecting agent that is 
so small or of such a nature that it will 
pass thru the pores of a Berkfield filter.” 
This led us to the conclusion that the 
foul-brood inspectors of the country might 
be compelled to quarantine an apiary where 
sacbrood might be found; but Dr. E. F. 
Phillips, in charge of apiculture in the 
bureau, does not think that this would be 
necessary. The disease at its worst is not 
very destructive; and when it does make 
its appearance it affects so few larvas in a 
colony that it need cause no great alarm. 
W’hile he might at times advise treating or 
isolating colonies, he does not believe it 
would be necessary to quarantine an apiary 
where it was found. 
STARVED OR NEGLECTED BROOD. 
There is another form of dead brood that 
very greatly resembles sacbrood; and that 
is, starved or neglected brood. Early in 
the spring, when natural pollen is scarce, 
and brood-rearing is well under way, some 
of the brood will die for the lack of the 
nitrogenous element of their food as' ob¬ 
tained from pollen. It is starved, not from 
a lack of honey, but from a lack of proper 
bread-and-milk diet made up of pollen and 
