HARRISON, DECEMBER, 1900. 49 
inserting a pin in either of these cells the same ropy mass may be 
drawn out. If an examination is made of the juices of the larve at 
different stages of the disease the bacilli may be seen. Spores form 
only after the death of the larve. The ropy decaying mass as well 
as the scales contain large numbers of these spores. 
Weighing these facts it seems quite probable that Harrison was 
working with but one disease, American foul brood. In his exami- 
nation of the ovaries of queens taken from foul-brood apiaries, 
Harrison reports the finding of bacilli in three queens. He reports 
that he found bacilli in a larger eu EES of eggs laid in an affected 
colony, and writes: 
In view of these facts, I am of the opinion that the eggs of bees from diseased hives 
may in some instances be infected. 
Harrison did not find Bacillus alvet in any case of chilled brood 
which he had examined and states that Mackenzie performed several 
experiments with chilled brood and never found this organism in 
any case where the brood had not been inoculated experimentally. 
Harrison writes as follows concerning the distribution of the disease: 
T have examined diseased larvee from Canada, from Europe (France, Switzerland, 
Austria, Germany, Italy and England), Cuba, and 13 States of the Union, ranging 
from New York to California and from Michigan to Florida, and have succeeded in 
isolating B. alvei from all of them. It is true that some of the cultures show certain 
differences, but they have not been sufficiently pronounced to constitute even a well 
marked variety of the species. 
Harrison may have isolated Bacillus alvei in limited numbers from 
material received from all these sources, but from his description of 
Bacillus alver one can not be sure that he always identified his culture 
correctly. 
It may be well at this point to consider Harrison’s description of 
the organism which he identified as Bacillus alver. In an abridged 
form it is as follows: 
Occurrence.—F ound in larve of bees suffering from a disease known 
as foul brood. 
Gelatin plates—The appearance of the growth depends upon the 
age of the colonies and character of the medium. In 24-36 hours 
at.22° C. the colonies are observed to be small, oval, or lozenge- 
shaped, bearing peculiar shoots extending frequently from one end 
and giving it a pear-shaped appearance. At the cnd of 48 hours the 
colonies are larger, with fine projections shooting out in all directions 
and forming circles. Later this appearance is destroyed by the 
liquefaction of the gelatin. 
Agar plates.—In 12 hours at 37° C. the colonies are small and burr- 
like. Further, concerning the growth on agar, he writes: 
On agar plates streaked with a light inoculation, most beautiful forms occur. The 
growth of the bacilli spreads over the surface and branches repeatedly, giving the 
13140°—Bull. 98 —12——4 
