_Prevention._ Measures directed toward the lessening of plethora tend to remove one of the most fruitful causes of the disease and though not invariably successful, are yet of great value. The most direct is the _abstraction of blood_ in the last fortnight of pregnancy, to the extent of 6 or 8 quarts. This tends to secure a lessening of the blood tension, and blood density, but there is the drawback of a created tendency to a subsequent increase in blood formation to make up the loss. This measure should be reserved for cows that are very plethoric, extra heavy milkers and such as have already suffered from the disease. _Purgatives_ will measurably secure the same end without the same degree of danger. One to two pounds of Epsom or Glauber salts in the last week of gestation, or at latest when labor pains set in, tend not only to remove solid or impacted masses from the first and third stomachs, and inspissated contents from the large intestines, but to secure a free depletion from the portal system. If not before, this should always be given immediately after parturition to cows in extra high condition, heavy milkers, and that have had a short and easy delivery. _Restriction of food_ for a week before and as long after parturition is of equal importance. A very limited supply of aqueous, easily digested, and laxative food (roots, sloppy bran mashes, fresh grass, ensilage) will meet the demand. _Exercise in the open air_ is of great value in giving tone to the muscles, and especially the nervous system, and in stimulating the emunctories and other functions. In the cold season _protection against cold draughts and chills_ must be seen to, and in the hot season the avoidance of an excess of solar heat and above all of the confined impure air of the barns. At midsummer and later, there is often great danger in the rich clover and alfalfa pasture, or soiling crop, with which the cow will dangerously load her stomach, and the only safe course is to remove predisposed animals and shut them up in a bare yard or box-stall. Under such simple precautions herds that had formerly suffered severely, have had the disease virtually put a stop to. In individual cases other measures are indicated. When the udder has reached an enormous size and development, and is gorged with milk, days before parturition, it should be systematically milked. The irritation in the gorged gland is quite as likely to induce premature parturition, as is milking, and, at the worst, the result is not so bad as an attack of parturition fever. Basing his advice on the fact that parturition fever does not follow a case of severe dystokia, Cagny applies sinapisms on the loins, croup and thighs of a fleshy, plethoric, heavy milking, parturient cow. Proof of their efficacy is not obtainable. Félizet advises leaving the calf with its dam for one week. Kohne doses the cow with nux vomica: Harms, with tartar emetic.