IT is only recently that the bacteriology of whooping-
cough has begun to assume definiteness, and even yet
there is no certainty that any of the various described
bacteria play any specific part in its etiology. In all
diseases of the respiratory apparatus the discharges are
almost certain to be so contaminated with the nasal and
oral bacteria as to make the isolation from them of a
single probably specific organism a matter of difficulty,
and its original recognition a matter of genius.
Of historical interest are the researches and observa-
tions of Deichler, Kurloff, Szemetzchenko, Cohn, Neu-
mann, Ritter and Afanassiew. Those of Kurloff and
Afanassiew are of especial importance because they opened
the way for the recent studies of Koplikl and those of
Czaplewski and Hensel.2 Koplik and Czaplewski and
Hensel worked entirely independently of each other, and
while the bacterium studied by the former differs in
several points from that of the latter, Czaplewski and
Hensel have claimed to see in Koplik's work a confirma-
tion of their own.
Koplik studied 16 cases of whooping-cough. The
sputum was collected in sterile Petri dishes, in which it
was allowed to stand for an hour or so in order that it
should break up into mucous fragments.
When the clear viscid expectoration from uncompli-
cated cases of whooping-cough is allowed to stand for an
1 CentralbL f. Bakt. u. Parasitenk., Sept. 15, 1897, xxii., Nos. 8 and 9,
2 Deutsche med. Woch., 1897, No. 57, p. 586, and CentralbL f. Bakt. u.
Parasitenk., Dec. 22, 1897, xxii., Nos. 22, 23, p. 641.