=Internal Exploration.= This is accomplished in the larger animals with the oiled hand in the rectum, the nails having been pared short and even to avoid injury to the mucosa. In ponies and yearlings the kidney may be felt, and this may be true also of mature animals of larger species in cases of hypertrophy or floating kidney. The ureters, bladder and intrapelvic urethra are easily felt in the male. The empty bladder lies on the anterior border of the pelvis; when full, it projects forward into the abdomen but retains its pyriform or, in the very young animal, its fusiform shape. In the female the sensation is somewhat modified by the presence on its upper surface of the uterus dividing into its two horns anteriorly. The single enlarged horn of pregnancy is especially misleading. The female urethra, cervix and bladder may be explored through the vagina. To explore the cervix vesicæ and urethra the fingers are slowly drawn back from the bladder along the median line of the floor of the vagina. In the _mare_ the cervix and adjacent portion of the bladder can be further explored with the index finger introduced through the opening of the urethra in the floor of the pelvis and at the junction of the vagina and vulva. In the cow the urethra is too small to be readily explored from within, and the orifice is still further guarded by the two lateral blind canals of Gærtner, into which the unskilled fingers more readily pass. Success only attends the careful search for the small central lower orifice. In the _smaller animals_ the finger only can be introduced into vagina or rectum and the urethra, cervix and bladder only can be felt. _The result of such exploration_ is straining even in healthy conditions but which becomes excessive in nephritis, pyelitis, renal, urethral, vesical or urethral calculus, cystitis, rectitis or enteritis. The _ureters_ are tender when inflamed, and they are swollen in calculus obstruction with an elastic feeling in front of the stone. The _bladder_ is very sensitive when overdistended, inflamed or pendent on the abdominal floor, or when the seat of calculus. In the absence of any liquid contents a calculus is felt as a hard solid mass firmly clasped by the contracted vesical walls. If liquid is present the solid hard calculus is felt movable in the fluid. An empty contracted bladder is firm and pyriform. An empty flaccid bladder, resulting from rupture or exhaustion, is flabby, with indefinite form and, if the seat of a lesion, tender. It varies in consistency with neoplasms (papilloma, sarcoma, carcinoma, or epithelioma). These have not the free mobility of the calculus floating in urine, and their point of connection with the wall may often be made out. When a solid body is felt, or suspected to be in the contracted bladder, an injection of sterilized water will usually facilitate diagnosis, and a differentiation of calculus and neoplasm.