WHOOPING-COUGH. 477

hour or so it separates into a fluid portion and a mass of
whitish, opalescent, irregularly formed flakes or frag-
ments. These were selected for study, and were trans-
planted by means of a platinum-wire hook to the cul-
ture-media. Czaplewski and Hensel used a rather better
technique than this, and secured purity of the bacteria
in the flakes by transferring them to a test-tube contain-
ing pepton solution and violently agitating the tube to
wash off foreign bacteria. After washing, the flakes were
sown upon culture-media.

Hydrocele-fluid was found most useful as a culture-
fluid, but particles of sputum were planted upon all
the culture-media, and attempts to cultivate bacteria from
them were conducted both aerobically and anaerobically.
In 13 out of the 16 cases the same bacillus (,r) was iso-
lated. The organism when stained and examined micro-
scopically appeared as a remarkably short and delicate
bacillus, shorter and more slender than the diphtheria
bacillus, measuring about 0.8-1.7 p in length and about
0.3-0.4/4 in breadth. When stained it appeared some-
what granular, and so resembled somewhat the diphtheria
bacillus. Old cultures presented similar involution-forms
to those seen in old cultures of the diphtheria bacillus.
In general the bacillus resembles the organism found by
Afanassiewl and others in cover-glass specimens of
whooping-cough sputum, but differs in that spores were
seen several times.

In pure cultures on coagulated hydrocele-fluid the ba-
cillus forms a finely granular layer of pearl-white color.

On agar-agar the cultures are opaque, pearl-white, and
occur as a thin layer.

The colonies upon agar-agar are whitish by reflected
light, and straw-yellow or deeper olive-green by trans-
mitted light. They are of an irregularly rounded shape
and are granular.

In gelatin puncture-cultures the growth resembles that
of the streptococcus, forming along the track of the wire

1 St. Petersburger med. Wock., 1887, Nos. 39-42.