PATHOGENIC SPIRILLA. 609 
supposes this to have been an epidemic of cholera nostras. Finally, Pfuhl 
(1894) found a vibrio in the north harbor of Berlin which from its growth in 
gelatin and pathogenesis for pigeons he believes to be identical with Vibrio 
Metschnikovi.” 
To the list of vibrios above referred to as resembling more or less 
closely the cholera spirillum we must add those described by Cun- 
ningham (1894) and obtained by him from the discharges of cholera 
patients. He has described “thirteen distinct forms obtained from 
cases of cholera and one of non-choleraic origin.” 
Pfeiffer and Issaeff (1894) report that they have found a sen- 
sitive test for the differentiation of these vibrios in the specific 
character of cholera immunity. They found that guinea-pigs which 
were immunized against cholera infection have a lasting immunity, 
and that the serum of such immunized animals has a specific ac- 
tion in protecting against infection by genuine cholera vibrios 
only, while for other species it has no action different from that 
of the blood serum of normal animals. In all cases where the cholera 
serum acted specifically the vibrios were promptly destroyed, while 
in cases where this specific action was absent the injected vibrios 
multiplied rapidly and caused the death of the animal. By means of 
this method the vibrios isolated from water—the phosphorescent 
vibrios of Dunbar, Vibrio Danubicus, Cholera Massanah—are shrwn 
to be distinct species, while the vibrio of Ivanoff behaves like the 
genuine cholera vibrio. In a subsequent paper Pfeiffer reports the 
interesting fact that a trace of highly active cholera serum, added to 
a culture of the cholera spirillum, when injected into the peritoneal 
cavity of a guinea-pig, within a surprisingly brief time causes the 
destruction of the cholera vibrios; whereas no such effect is produced 
upon other species. A similar destruction occurs when cholera vib- 
rios are injected into the abdominal cavity of immunized guinea- 
pigs. The researches of Dunbar (1894) indicate that Pfeiffer’s test 
is not so reliable as he supposed; and also that phosphorescence can- 
not be relied upon for distinguishing similar water bacteria from 
genuine cholera vibrios. Rumpel has reported the fact that two un- 
doubted cultures of the cholera spirillum, from different sources, after 
being passed through pigeons and cultivated for some time in arti- 
ficial media, showed phosphorescence. One of these cultures was ob- 
tained originally from the discharges of Dr. Oergel, who was a vic- 
tim to cholera from laboratory infection (case reported by Reincke, in 
the Deutsche medicinische Wochenschrift, No. 41, 1894). Anvther 
case of supposed laboratory infection, in which recovery occurred, is 
reported by Lazarus, in the Berliner medicinische Wochenschrift, 
1893, page 1,241. 
That cholera vibrios may be present in the alimentary canal of 
39 
