BACTERIA IN CROUPOUS PNEUMONIA. 407 
but especially to the dependent portions of the body. Occasionally there is 
a little pus near the puncture, but usually death occurs before the cellulitis 
reaches the point of producing pus. The subcutaneous connective tissue 
contains a quantity of Vieods serum, which possesses virulent properties and 
which contains a multitude of micrococci. There is usu: lly more or less in- 
flammatory adhesion of the integument to the subjacent tissues. The liver 
is sometimes dark-colored and gorged with blood, but more frequently it is 
of a lighter color than normal and contains much fat. The spleen is either 
normal in appearance or enlarged and dark-colored. Changes in this organ 
are more marked in those cases which are of the longest duration. 
‘The blood commonly contains an immense number of micrococci, usually 
joined in pairs and having a diameter of about 0.5 “. These are found in 
lood drawn from superficial veins, from arteries, and from the cavities of 
the heart immediately after death, and in a few cases their presence has been 
Fig. 95.—Micrococcus pneumonie croupose in blood of rabbit inoculated with pneumonic spu- 
tum. x 1,000. 
verified during life. Observations thus far made, however, indicate that it 
is only during the last hours of life that these parasites multiply in the cir- 
culating fluid, and in a certain proportion of the cases a careful search has 
failed to reveal their presence in the blood in post-mortem examinations 
made immediately-after the death of the animal.” 
Tn animals which are not examined until some hours after death 
a considerable increase in the number of micrococci occurs post mor- 
tem. The fact that this micrococcus varies very much as to its 
“pathogenic power, as a result of conditions relating to the medium in 
which it develops, was insisted upon in my first published paper, and 
has been fully established by later researches (Frankel, Gameléia). 
Susceptible animals inoculated with attenuated cultures acquire an 
immunity against virulent cultures. 
In dogs subcutaneous injections usually give a negative result, 
or at most a small abscess forms at the point of inoculation. In a 
a ij 
