_Microscopical examination._—Bits of muscular tissue, taken from various points, were teased out in salt solution and the condition of the muscle fibers noted. Smear preparations were also made from bits of muscular tissue and from the bone marrow, and these were stained and subjected to microscopical examination. Portions of the meat were also hardened and cut into microscopic sections, which were stained and mounted for histological and bacteriological study. _Bacteriological examination._—In the bacteriological examination of sour hams, especial attention was directed to the detection of anaerobic species, as it seemed reasonable to suppose that if the changes taking place in sour hams were due to bacteria these bacteria would in all likelihood be anaerobes (i. e., organisms which develop in the absence of oxygen). This assumption was based upon the fact that, as a rule, souring begins in the interior of the ham next to the bone, and, furthermore, the hams are cured in large vats where they are completely submerged in the pickling fluids, so that any bacteria which develop within the bodies of the hams while they are in cure are probably restricted to practically anaerobic conditions. Cultures were made from the interiors of the hams at various points by first searing the cut surface thoroughly with a heavy metal spatula and then cutting out, by means of sterile scissors and forceps, plugs of meat about 1 cm. square. The plugs of meat were then dropped into tubes containing the egg-pork medium and pushed down to the bottom of the tubes, where they were held in place by the chopped meat above; in this way conditions favorable for the development of anaerobic organisms were obtained. In inoculating the pork-agar tubes, the medium was first boiled to expel any inclosed air and cooled to 43° to 45° C; the plugs of meat were then dropped into the tubes and the agar rapidly solidified by plunging the tubes in cold water; in this way the bits of meat were inclosed in the agar at the bottom of the tubes, affording suitable conditions for anaerobic growth. Aerobic and anaerobic plates were also made from the meat, and in most cases bouillon tubes were also inoculated. Cultures were always taken from the bone marrow as well as from the meat. Novy jars were also used for obtaining anaerobic conditions in growing the cultures. _Chemical examination._—In order to determine whether the souring was connected with or dependent upon a lack of penetration of the pickling fluids to the interior of the meat, the hams were further subjected to a chemical examination and the content of the meat in sodium chlorid and potassium nitrate determined at varying depths. RESULTS OF EXAMINATION OF SOUR AND SOUND HAMS.