Horses rearing up on end, so as to stand nearly perpendicular upon their hind legs, is the most dangerous of any description, even to the most judicious, expert, and experienced horseman; who has, in such aukward predicament, (particularly when a horse most viciously repeats it,) no alternative, but to slacken his reins, and lean his body close to the neck, the better to expedite so critical a preponderation. Horses inclined to run away, from an impetuosity of temper, and an eagerness to get forward, frequently alarm their riders, if they are exceedingly irritable upon the score of _timidity_, or terrified upon the principle of inexperience; but sportsmen mostly prefer horses who require the _curb_, to those who want _a spur_, well knowing the utility of moderately dropping the hand, and indulging the loose occasionally; as a _dead pull_ at a hard-mouthed run-away horse, is the sure means of making him endeavour to continue his career the longer. VIPER, BITE OF.—See VENOMOUS BITES. VISCIDITY OF THE BLOOD—is that state in which the blood is frequently known, when, by a collapsion of the pores, (from some of those causes which produce colds, coughs, and inflammatory diseases,) it acquires a preternatural consistence from the external repulsion of the perspirative matter, which, thrown upon the circulation, constitutes a _siziness_ of the _blood_: this, by its retention, becomes so viscid and adhesive, (or tough,) that, when it has been drawn off by bleeding, and set by two or three hours to cool, it is with difficulty separated upon the surface, even with the sharpest penknife. Horses having their blood in a state too _sizy_ and _viscid_ for the perfect purposes of secretion and health, soon display it in some way or other: a heaviness of the head, a dulness of the eyes, a lassitude of the body, a husky tendency to cough, a rough harshness in the coat, a swelling of the legs, or cracks in the heels, (particularly if it happens in the winter season,) are some of the indications by which it may be readily known, and should be speedily counteracted. Unloading the vessels, by twice bleeding, about ten days apart, attenuating the crassamentum of the blood by mild diuretics, and altering its property by a short course of alterative powders, will prove all that is necessary to promote and ensure condition.