86 HISTORICAL NOTES ON BEE DISEASES. 
keepers to the important relation which exists between the etiology 
of a disease and its rational treatment. 
The author at first deemed it advisable to direct the attention of 
his hearers to a consideration of the nature of disease. A brief dis- 
cussion is then given of the etiology of diseases, illustrating the state- 
ments made mainly by citing phenomena observed in bee diseases. 
In discussing the etiology, the usual division into predisposing and 
exciting causes is made. Of the predisposing causes of diseases it 
seemed well to mention age, sex, heredity, race, climate, and pre- 
existing disease, masmuch as these factors may be active in one or 
more of the diseases of bees. Of the exciting causes of disease, food 
and microorganisms are the only ones mentioned, since food, bacteria, 
protozoa, and fungi have been thought by one writer or another to 
be the direct exciting cause of bee diseases. A brief reference is 
then made to the nature of bacteria, protozoa, and fungi. 
Mention is made in the paper of the fact that a microstructure had 
been encountered in the investigations of European foul brood which 
had failed to grow on artificial media. This was referred to as 
“Bacillus Y.’ Some hope was entertained that it might sometime 
be proved to be the exciting cause of the disease. The great resistance 
exhibited by the spores of Bacillus larve toward disinfectants was 
emphasized by citing some preliminary experiments. 
The following are some of the facts to which the attention of the 
bee keepers was directed: 
1. Disease is nothing more than a departure from a state of health. 
2. The departure is the result of some cause. 
3. The cause is, as arule, a combination of factors which constitute 
what is known as the etiology. Age, sex, race, and climate seem to 
figure as predisposing factors in bee diseases. Bacteria, protozoa, 
and fungi have all been studied as probable exciting causes. Bac- 
teria are the only kind of a microorganism that has been proven to 
be the cause of a bee disease. | 
4, Comparatively little is known of the etiology of bee diseases— 
a statement which, as one becomes familiar with the diseases of other 
animals and man, is found to be true for them also. 
5. The exciting cause of but one bee disease is positively known. 
6. A rather interesting microstructure was encountered in Euro- 
pean foul brood which had refused to grow when sown upon artifi- 
cial media. This is referred to as “‘ Bacillus Y.” 
7. A treatment, either preventive or curative, can best be devised 
only after the cause is determined. 
8. Before treating a disease, a diagnosis is advisable. This can 
most accurately be done by knowing the cause and finding it in the 
diseased body. 
