PROTECTIVE INOCULATIONS. 339 
the publication of the paper from which the above quotation is made. 
Under these circumstances the writer feels justified in again calling 
attention to his priority in the discovery of this important pathogenic 
micrococcus, and in objecting to its being described as “Frankel’s 
pneumococceus,” the “ diplococcus of Frankel,” ete. 
In my paper above referred to (July, 1885) I described this micro- 
coccus under the name of Micrococcus Pasteuri, but in my “Manual 
of Bacteriology ” (1892) it is described under the name of Jicrococeus 
pneumonice crowpose. 
This micrococcus is very pathogenic for mice and for rabbits, less 
so for guinea-pigs and for dogs. Like other pathogenic microérgan- 
isms of the same class, it varies greatly in virulence when obtained 
from different sources. In the saliva of healthy persons, which 
seems to be its normal habitat, it sometimes has comparatively little 
virulence. On the other hand, when contained in the blood or in an 
exudate from a serous cavity of an infected rabbit or mouse, it is very 
virulent. In one instance (1881) the writer has seen a fatal result in 
a dog from the subcutaneous injection of one cubic centimetre of bloody 
serum from the subcutaneous connective tissue of a rabbit recently 
dead. 
Pneumonia never results from subcutaneous injections into sus- 
ceptible animals, but injections through the thoracic walls into the 
lung may induce a typical fibrinous pneumonia. This was first de- 
monstrated by Talamon (1883), who injected the fibrinous exudate of 
croupous pneumonia, obtained after death, or drawn during life by 
means of a Pravaz syringe, from the hepatized portion of the lung, 
into the lungs of rabbits. Gameleia has also induced pneumonia in 
a large number of rabbits, and also in dogs and sheep, by injections 
directly into the pulmonary tissue. Sheep were found to survive sub- 
cutaneous inoculations, unless very large doses (five cubic centimetres) 
of a virulent culture were injected. But intrapulmonary inoculations 
are said to have invariably produced a typical fibrinous pneumonia 
which usually proved fatal. In dogs similar injections gave rise to 
a “frank, fibrinous pneumonia’ which rarely proved fatal, recovery 
usually occurring in from ten to fifteen days, after the animal had 
passed through the stages of red and gray hepatization characteristic 
of this affection in man.” 
Without doubt an attack of pneumonia is followed by a certain 
degree of immunity of longer or shorter duration. According to 
Ruge, who'has made a careful study of the subject, relapses are 
very infrequent—indicating a temporary immunity—but subsequent 
attacks are more likely to occur in those who have once suffered an 
