241. Hence in every state of the system in which the vital energy of the blood is preternaturally increased, coagulation is proportionably slow; in every state in which its energy is diminished, coagulation is rapid. By copious and repeated blood-letting, the vital energy is rapidly exhausted. The effect of blood-letting on coagulation is determined by experiments instituted for the express purpose of ascertaining it. Blood was received from a horse at four periods, about a minute and a half intervening between the filling of each cup. Minutes. Seconds. In cup No. 1. coagulation began in 11 10 " 2. " " " 10 5 " 3. " " " 9 55 " 4. " " " 3 10 242. In like manner three cups were filled with the blood of a sheep, at the interval of half a minute. Minutes. Seconds. In cup No. 1. coagulation began in 2 10 " 2. " " " 1 45 " 3. " " " 0 55 The same result was obtained in blood taken from a human subject. A pound and a half of blood was removed from the arm of a woman labouring under fever, a portion of which, received into a tea-cup on the first effusion, remained fluid for the space of seven minutes; a similar quantity, taken immediately before tying up the arm, was coagulated in three minutes thirty seconds. These experiments demonstrate that coagulation is rapid or slow as the vital energy of the blood is exhausted or unexhausted, or that in proportion to the degree of life possessed by the blood is the space of time it takes in dying.