228                     Corynebacterium equi in a She-Buffalo

                                   TABLE I— concld.

It is, therefore, evident that the organism isolated has characters identical
with those of C. equi.

                              SEROLOGICAL TESTS

(1) Agglutination.—When the material was first received, suspecting
the case might be one of abortion due to infection with Br. abortus—the
common causal organism of bovine abortion—a guinea-pig had been inoculated
intra-peritoneally with the material. This was bled twenty-seven days
later, and the separated serum was put to agglutination test against the or-
ganism under report as well as against Br. abortus. No agglutination took
place in any dilution in both instances.

Two rabbits were immunised, one with C. equi of foal pneumonia origin
and the other with the diphtheroid from the specimen. They were injected
intravenously with saline emulsions at four hundred millions per c.c. of the
respective organisms, three times at five days intervals. The dosage for the
successive injections was 0.25, 0.5 and 1 c.c. respectively. They were bled
on the eighth day after the last injection. The two sera were put to the
agglutination test against their homologous organisms. At the same time
they were put to cross-agglutination tests, the serum of the equine source
against the buffalo-strain of diphtheroid, and vice versa. No agglutination
was obtained in any of these tests. These tests were repeated in saline con-
centrations up to 1 . 5 per cent, still with negative results.

The fact, that the guinea-pig serum failed to reveal any titre for the
organism isolated and the sera of rabbits specially treated. for the purpose
also failed to give any agglutination, is not, however, very disappointing.
For, working with C. equi isolated from, cases of foal pneumonia, we have
never been able to demonstrate agglutinins in the naturally infected subjects,
and only occasionally in small animals intensively treated for the production
of agglutinating sera. This seems to have been the experience of most other