14 MEETING OF INSPECTORS OF APIARIES. 
lum which is followed by a slow digestion or liquefaction of the 
easein; Bacillus larve does not grow in milk. In litmus milk, 
Bacillus coli communis produces a large amount of acid, which is 
indicated by the change of the litmus to the red color; Bacillus alvei 
produces no marked change in reaction, and Bacillus larve does 
not grow in this medium. In the bouillons to which the sugars, 
glucose, lactose, saccharose, ete., have been added, there is produced 
by the growth of Bacillus coli communis, gas, and a large amount of 
acid; Bacillus alvei does not produce gas and only a small amount 
of acid by its growth in the media containing sugars, while Bacillus 
larve does not grow when planted in these “soils.” (I shall 
speak later of a medium upon which Bacillus larve will grow.) 
It is by these differences which we observe in the growth upon the 
various media and the effect produced upon the different media by 
the growth of the bacteria that we are able to determine one species 
of bacteria from another. 
THE RESULTS OF THE ACTIVITY GF BACTERIA. 
In the consideration of this question it is convenient to divide the 
bacterial flora into two groups—nonpathogenic, or those which do not 
produce disease, and pathogenic, or those which do produce disease. 
Some of the nonpathogenic bacteria are economically very important 
as scavengers. The bodies of dead animals and plants are largely 
brought to decay by them. The flavors of butter, cheese, and wines 
are thought to be improved by the growth of bacteria or other micro- 
organisms—the fungi and the yeasts. Others of these micro-organ- 
isms ruin the food, causing the souring of milk, the spoiling of fruit, 
etc. Many diseases in man and animals are known to be caused by 
bacteria, as tuberculosis, diphtheria, glanders, and anthrax. 
I wish now to speak briefly of how bacteriology has been used in 
the study of bee diseases, and to summarize the results which have 
been obtained. For a more detailed account you are referred to a 
bulletin issued by the Bureau of Entomology of the United States 
Department of Agriculture—Technical Series, No. 14, * The Bacteria 
of the Apiary, with Special Reference to Bee Diseases,” issued 
November 6, 1906. 
From what has been said one would naturally infer that in every 
apiary, whether diseased or not, there are en the hives, combs, and 
bees a large number of bacteria that are perfectly harmless. If one 
is trying to find in a diseased apiary the species of bacteria which is 
the probable cause of the trouble, what is the method of procedure ? 
Suppose there were two herds of cattle on adjoining farms and the 
cattle on one farm were dying while those on the other remained well. 
If it were suspected that some plant which the cattle were ating wasthe 
