A NEW CHROMOGENIC MICROCOCCUS. 
Mary HEFFERAN. 
(WITH FOUR FIGURES) 
Ix the course of an examination of river water for the Sani- 
tary District of Chicago, carried on during the past year under 
the direction of Professor Jordan at the University of Chicago, 
asomewhat unusual opportunity has been afforded for the study 
of water bacteria. The water for this examination is taken from 
twenty-seven different stations along the Illinois and Desplaines 
tivers and their tributaries, and also from the Mississippi river 
mere and below St. Louis. It is collected in sterile bottles with 
roti fitting glass stoppers. As soon as the water is collected 
these bottles are enclosed in small tin cans which are packed 
with ice in larger cans, and shipped as speedily as possible to 
Chicago, 
. making a qualitative examination of this water it has been 
a ordinary beef peptone agar (Witte’s) and in Nahrstoff 
“eyden agar.* The latter medium has the advantage of bring- 
es development a much greater number of colonies than 
nea peptone agar; for instance, at the end of ten days a 
Si agar plate and the corresponding one of Niahrstoff 
for . may Present colonies in a ratio of 21:400. The oe 
oO difference has not as yet been Ber 
gtowing at i . poeipie that the large, spreading, and rap! iy 
OTMs on q onies may inhibit the development of the more ee o 
these large Eeene “—"t plate. On the Nahrstoff Heyden p 
seen, or “ am particularly the fluorescent forms, are ek 
sae — appear only as small dots ; while on the . 
ing io 1S etowded with small, distinct, slowly — a8 
tics, Jf ony of which seem to present novel mee ae 
Varieties not a » therefore, that this medium will furnish 
ae . tained on peptone media. 
1900] ledner, Zeitschr. f. Hygiene 19: 460. 
261 
