BACTERIOLOGICAL NOTES 35 
colonies. At the end of twenty-four hours it was often 
impossible to see anything on the surface of the agar 
without the use of a lens. The colonies appeared as 
pin points among the larger colonies of other bacteria, 
and at times it was very difficult to isolate the bacillus 
on account of the overgrowth of other organisms. Blood 
cultures were taken as a routine measure at all autopsies, 
and at first nothing grew but the organisms of the 
secondary infections. Later, however, the method was 
changed. The heart was opened aseptically, and from 
I cc. to 5 c.c. of blood drawn off with a pipette and 
planted in a flask containing 50 c.c. of broth, or dis- 
tributed in several tubes of broth. After twenty-four 
hours in the incubator, plates were made, or slope agar 
inoculated in successive tubes. Such blood cultures were 
taken in 63 cases. In 29 the cultures were positive, the 
bacilli being found in 18, in 13 of which it was uncon- 
taminated, in 3 associated with staphylococc:, and in 2 
with unidentified bacteria. The remaining 11 positive 
blood cultures had staphylococci only in 6, staphylococci 
with an unknown bacterium in 1, and unidentified 
bacteria in 4 cases.” 
The characteristics of the organism were : 
Short slender bacillus, 0°5 to 2°0 » by o'5 yw, found 
singly or in pairs; sporeless, flagellated, actively and 
progressively motile ; Gram-negative, and not staining 
readily with ordinary stains, but with Loeffler’s methy- 
lene-blue shows a characteristic bipolar appearance; no 
liquefaction of gelatin or coagulation of milk or gas 
formation. After twenty-four hours’ incubation on agar, 
there is a moist dew-drop growth, which later becomes 
larger and opaque ; bouillon cloudy ; older growth with 
heavy stringy sediment ; potato tan; light tan in twenty- 
four hours to dark tan in three weeks; medium also 
becomes tanned. 
When cultures are taken early in the disease, the 
B. bronchisepticus is found in the respiratory tract in 
every case, and if taken in the first stage is found 
