In preparations made by teasing out bits of the meat in physiological
salt solution, the cross striation of the muscle fibers from the sour
areas was found to be much less distinct than in similar preparations
taken from sound portions of the meat or from sound hams. At times it
was found that the muscle fibers in the sour areas had completely lost
their cross striæ, but the longitudinal striation could still be made
out. In cases where the souring was pronounced there was sometimes
complete loss of both longitudinal and cross striation; in these cases
the muscle fibers appeared to have undergone slight swelling and the
protoplasm exhibited a finely granular appearance.
In stained sections of the sour meat another striking change was
noticed in the disintegration of the nuclei of the muscle fibers, which
are at times completely broken up, appearing as bluish granular masses
in sections stained with hematoxylin and eosin. (Compare figs. 1 and 2
of Pl. I.)
In sections stained by the Gram-Weigert method to show the presence of
bacteria, a large Gram-staining bacillus was noted between the muscle
fibers in the connective-tissue elements of the muscle. In some of the
sections these bacilli were present in great numbers, sometimes in
densely packed clumps or masses, while in other sections, or in other
portions of the same section, they were only sparsely distributed
between the muscle fibers. Where the bacteria were more numerous the
histological changes in the muscle fibers, especially the breaking
down of the nuclei, were more noticeable. The intermuscular connective
tissue had apparently furnished paths of least resistance along which
the organism followed. In Plate II, figures 1 and 2, the bacteria are
shown between the muscle fibers under low and high power magnifications.
In Plate II, figure 1, under the low-power magnification, the bacteria
appear as dark clumps or bands between the muscle bundles. Under the
high power they are shown following along the sarcolemma sheaths
between the muscle fibers.