Mar. 12,19x7 
Spore-Forming Bacteria of the Apiary 
411 
GeeaTin stab. —Liquefaction proceeds slowly until complete. A gray 
membrane forms at the surface, and gray flakes float in the liquefied 
medium. 
Indol. —A very strong pink coloration takes place on adding the 
reagents. 
Nitrate. —Reduction to nitrite was positive for one of the two strains 
tested and negative for the other. 1 2 
The description of B. orpheus is not as complete as it might be made. 
This is owing to the fact that it was only decided rather late in the course 
of preparation of the paper to include a description of B . orpheus at all. 
Fig. x .—Bacillus mesentericus: Smear from an 18-hour-old agar slope. 2 X 1,480. 
The description is based on the behavior of two different strains in the 
different media. White (18) discovered and named this organism in 1912. 
The following brief characteristics should aid in the identification of 
these spore-forming organisms: 
(a) B. vulgatus forms a heavy, wrinkled growth on potato (PI. 94, A ); 
B. mesentericus , a less luxuriant, netlike growth (PI. 94, B). 
(1 b ) Even under low magnification, cultures on agar plates show that 
B . vulgatus (PL 93, B) grows in curves much resembling B. anthrax , while 
1 In old cultures of agar and plain milk a decided green coloration of the medium is noted. 
2 The drawings reproduced in figures i to 6 and Plate 93 were made with the aid of a camera lueida, the 
image being projected to the base of the microscope stand. The photograph of the potato cultures was 
made for the author by Dr. James A. Nelson, of the Bureau of Entomology. 
