With a well-formed cow and calf and a natural presentation as above, calving is usually prompt and easy. Obstacles may, however, come from failure of the mouth of the womb to dilate; from twisting of the neck of the womb; from tumors in the vagina; from dropsy in the womb or abdomen; from overdistention of the rectum or bladder; from undue narrowing of the passages; from excess of fat in the walls of the pelvis; from the disturbance of a nervous cow by noises; from stone or urine in the bladder; from wrong presentation of the calf, its back being turned downward or to one side in place of upward toward the spine of the dam; from the bending backward of one or more limbs or of the head into the body of the womb; from presentation of the back, shoulder, or croup, all four limbs being turned back; from presentation of all four feet at once; from obstruction caused by an extra head or extra limbs, or double body on the part of the offspring (Pl. XIX); from dropsy or other disease of the calf; from excessive or imperfect development of the calf; from the impaction of twins into the passages at the same time; or at times it may be from the mere excessive volume of the fetus. GENERAL MAXIMS FOR THE ASSISTANT CONCERNING DIFFICULT PARTURITION. Do not interfere too soon. "Meddlesome midwifery is bad" with animals as with women. After labor pains set in, give a reasonable time for the water bags to protrude and burst spontaneously, and only interfere when delay suggests some mechanical obstruction. If there is no mechanical obstruction, let the calf be expelled slowly by the unaided efforts of the cow. Bruises and lacerations of the passages and flooding from the uncontracted womb may come from the too speedy extraction of the calf. When assistance is necessary, the operator should dress in a thick flannel shirt from which the sleeves have been cut off clear to the shoulders. This avoids danger of exposure and yet leaves the whole arm free and untrammeled. Before inserting the hand it and the arm should be smeared with oil, lard, or vaseline, care being taken that the oil or lard is fresh, neither salted nor rancid, and that it has been purified by boiling or rendered antiseptic by the addition of a teaspoonful of carbolic acid to the pound. This is a valuable precaution against infecting the cow by introducing putrid ferments into the passages and against poisoning of the arm by decomposing discharges in case the calving is unduly protracted. When labor pains have lasted some time without any signs of the water bags, the dropping in at the sides of the rump, and the other preparations for calving being accomplished, the hand should be introduced to examine. When the water bags have burst and neither feet nor head appear for some time, examination should be made. When one fore foot only and the head appear, or both fore feet without the head, or the head without the fore feet, examine. If one hind foot appears without the other, make examination. The