In order to throw some light upon this point, a number of fresh
hams—that is, hams which had been chilled but not pumped or subjected
to any other manipulation—were examined bacteriologically, but in no
case could the anaerobic bacillus which was isolated from sour hams
be detected in any of them. The fact that in certain of the smaller
packing establishments which cure their hams without pumping the
percentage of souring is extremely low would also seem to negative this
possibility, for if the bacillus which causes souring were present in
the hams at the time of slaughter, sour hams would be as frequent at
such establishments as at those establishments which make a practice of
pumping. Furthermore, a laboratory study, biological and chemical, of
the bacillus isolated from sour hams shows that this organism belongs
to the class of putrefactive bacteria, and while such bacteria may be
present in the intestines of healthy animals, as, for example, the
bacillus of Bienstock (_Bacillus putrificus_), these bacteria do not
invade the organs and tissues of the body until after the death of the
animal, and the packing-house practice of rapidly eviscerating the hogs
immediately after slaughter would certainly preclude this possibility.