_Hæmorrhoids or piles_, consist in a dilatation of the veins of the lower portion of the rectum, with a thickening of their walls, and increase of surrounding fibrous tissue. They may be internal or external. The contained blood may coagulate forming a thrombus. The walls may rupture, giving rise to hæmorrhages, or become inflamed and suppurate. _Abnormal contents._ The normal contents of the bowels may be found mixed with the various products of inflammation, including mucus, serum, blood and pus. Biliary calculi and foreign bodies of various kinds, may be found, which may have produced no effects, or they may have served as nuclei, around which the salts of lime, bile, mucus, fæcal matter, etc., may have accumulated, producing intestinal concretions. =Parasites.= The intestinal canal is infested by several forms of entozoa, among which may be found the following: _Ascaris lumbricoides_; the common round worm, six to ten inches in length. It may be single or in large numbers. _Oxyuris vermicularis_; a small white worm, measuring from two to four lines in length, and found only in the large intestines, and mainly in the lower part of the rectum, where they may be present in large numbers. _Trichina spiralis._ This parasite is found in the small intestine, and only in its adult form. It measures from less than a line, to two lines in length. The embryos penetrate the walls of the intestine, and finally locate in the muscles, where they remain encapsulated. If a portion of this muscle is eaten by another animal, the larvæ again become active, and acquiring the mature sexual form, reproduce, the young embryos again migrating to the muscles. _Tricocephalus dispar._ Found only in the head of the colon, and measures one and a-half to two inches in length; neck long, and body of male covered with wart-like appendages on one side. _Distoma lanceolatum._ Flat, lancet-shaped, and transparent, a-half inch long, one-quarter wide. Rarely found in upper portion of small intestines, natural habitat appearing to be in the bile passages. Of tapeworms, the following varieties may be found: _Tænia solium._ Head about the size of a pin-head, and furnished with sucking disk and double row of hooks; neck long and narrow; body flat and jointed, each segment about a-half inch in length; body may be from ten to fifty or more feet in length. _Tænia mediocanellata._ Head truncated and destitute of hooks; body jointed and of great length. _Tænia flavopuncta._ Very rare. Yellow spot at the middle of each joint. _Bothriocephalus latus_, (broad tapeworm.) Head long, unarmed; neck inconspicuous; body composed of about two thousand joints; mature joints broader than long. Section IV. THE PANCREAS.