1900] CHROMOGENIC BACTERIA 379 
others red, green, violet, purple, or yellow. These colors, as will be 
shown, can generally be controlled, thus permitting one to obtain 
at least part of the colors with certainty. This interesting fact 
las already been pointed out by the authors.3 In addition to the 
pigment described below, colored insoluble microscopic crystals 
are also generally found on solid media. These crystalline 
aggregates are made up of irregular radiating clusters of fine 
needles of a deep blue color, and are probably not due toa crystal- 
lization of the pigment, but to crystals of some other substance 
stained by it. The composition of these crystals will be dis- 
cussed in a future communication. ; 
The organism liquefies gelatin, solidified blood serum, albu- 
min (white of egg), fibrin, etc. In peptone solutions no indol is 
| produced, neither does the bacillus produce gas in fermentation 
tubes filled with glucose or lactose peptone solutions at room 
femperature nor at incubator temperature. 
The bacilli themselves are generally colorless, rarely they 
appear red or blue; in some of these latter cases the organism 
i uniformly stained, at others times only minute intra-bacillary 
slanules are colored. The bacillus is polymorphic; not only 
does its form vary according to the nutritive media employ ed, 
but often there is great variation in form observed in different 
Portions of the same medium. It has not been possible thus 
far to obtain with any degree of certainty a constant form on any 
culture medium, not even when employing one of definite com- 
Position (7. ¢., a medium in which the source of nitrogen 1s eet 
Peete etc. but a chemical compound of known composition 
Such as asparagin or other bodies). In general the organism 
“sumes the form of a short rod rounded at the ends, at other 
limes it is spherical; again, long curved giant forms with swollen 
“tds are seen. The bacilli are sometimes isolated, oogenenarn 
stouped (diplo-bacilli, chains). Coccus forms are ee of 
of a = staphylo- and diplo- forms, or as tetrads and chal 
“ight cells 
3 
ator, E. et Tuiry, G.: Bacille polychrome. 
* Communication 4 la Réunion Biologique de Nancy, 
Cultures et Spectre du Pig- 
Feb. 1898. 
