172 , REPORT OF THE COMMISSIONER OF AGRICULTURE. 
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capped over, but the cell cap, commonly of a darker color than that covering a healthy 
brood, settles, leaving the cover concave instead of flat or convex, and shortly small , 
holes appear, as if Inquiry had been instituted to learn the condition of the cccu- 
pant, or to liberate the gases and cdor and facilitate evaporation. Torn and ragged 
cell caps are frequent, and some ceils may be empty and cleansed; and in the midst 
of ragged and sunken caps a live bee may occasionally emerge. 
The means by which these deadly agents are commonly introduced into the hive 
and into the bodies of their victims has not been certainly determimed. Prof. Frank 
R. Cheshire, F. L. §., F. R. M.S., to whom we are indebted for the classification of 
this species of Bacillus, and also for much that is valuable concerning its life his- 
tory and pathogenic character, speaking of the means of propagating this disease, 
says (see Bees and Bee-Keeping, vel. 2, pp. 157, 158, London, 1888): 
‘** My strong opinion is, that commonly neither honey nor pollen carry the disease, 
but that the feet and antenne of the bees usually do.” ‘‘ tt is also extremely likely 
that spores are carried in the air and taken in by the indraft set up by the fanners. 
There will be no difficulty in this supposition when it is remembered that the organ- 
isms are so minute that a cubic inch of material wouid form a quadruple line of 
them from London to New York.” 
My own experience and observation is in agreement with this last proposition, as 
witness the following paragraph from my report of last year (see Report of U. 
S. Entomologist, 1886, p. 587): 
“That the contagion may sometimes be borne from hive to hive by the wind ap- 
pears to be true, as it was observed in one of the apiaries which | treated for this 
disease during. the past summer that of a large number of diseased colonies in the 
apiary, with the exception of two cclonies all were located to the northeast of the 
colony in which the disease first appeared. The prevailing wind had been from 
the southwest.” 
Mr. Cheshire says further, page as above: ‘‘The bee-keeper is unfortunately 
almost compelled to become himseit a probable cause of infection. His hands, 
made adhesive by propolis, carry the spores or bacilli, and so may transfer them, 
even hours later, to healthy hives. The clothes should be kept as far as practicable 
from contact with suffering colonies, and the hands after manipulating them should 
be disinfected by washing with a weak solution of mercuric chioride (corrosive 
sublimate), one-eighth of an ounce in 1 gallon of water being quite strong enough.” 
The concluding paragraph under this heading in my report for 1886 is as fol- 
lows: 
‘That the disease germs may be carried upon the clothing and bands appears prob- 
able, from the fact that in one neighborhood this disease appeared in only two apia- 
ries, the owners of which had spent some time working among diseased colonies at 
some distance from home, while other apiarisis in that locality who had kept away 
from the contagion had no trouble from foul-brood.” 
It has been the common belief that honey is the medium through which the dis- 
ease is most frequently introduced from both near at hand and remote sources of 
infection. That undue importance has been attached to honey as the common 
source of infection appears certain, for I have proved by repeated trials that if 
frames containing combs of capped honey, and having no cells containing pollen, 
be removed from infected hives and thoroughly sprayed or immersed, using an 
acid and alkaline solution of suitable strength to destroy the germs exposed to its 
action, the honey in such combs did not communicate disease when placed in 
healthy colonies and consumed by the bees as food for both summer and winter 
uses. Ihave found it altogether practicable to feed honey which had been extracted 
from infested combs without boiling, always adding, however, as a precaution, a 
disinfectant suitable to destroy any infection pessibly lurking in such food, 
In speaking of honey as a means of carrying this contagion, Mr. Cheshire says : 
‘“‘T have searched most carefully in honey in contiguity with cells holding dead 
larvae; have examined samples from stocks dying out with rottenness; inspected 
extracted honey from terribly diseased colonies, and yet in no instance have I found 
an active bacillus, and never have been able to be sure of discovering one in the 
spore condition, although it must be admitted that the problem has its microscopic 
difficulties, because the stains used to make the bacilli apparent attach themselves 
very strongly to all pollen grains and parts thereof, and somewhat interfere with 
examination. I have now discovered that it is impossible for bacilli to multi- 
ply in honey, because they can not grow in any fiuid having an acid reaction.” 
‘As to pollen being the medium by which this contagion is commonly introduced 
into the hive, not wishing to appear as speaking ex cathedra, I venture to say that 
further experiments in the line indicated in my report of last year leave little room 
to doubt the accuracy of the opinion then formed, namely, that pollen is the me- 
dium by which this contagion is most commonly introduced, and most rapidly 
