The method, at least when used at half-minute intervals, did not reveal in all instances the same degree of clotting. Usually, when the process was very rapid, the revealed clot was a thick jelly; whereas, when the process was slow, a strand of fibrin or at most a small amount of jelly was found. This difference in the _degree_ of coagulation introduced, of course, an element of inexactness. In our experiments, however, this inexactness was unfavorable to the result we were seeking for, i. e., the acceleration of the process--because the jelly is a later stage than the fibrin strand; and since we nevertheless obtained good evidence of acceleration, we did not in these experiments attempt to determine more accurately differences in the stage of the clotting process. 5. _Cleaning of apparatus._--After the wire was removed from the tube, the clot attached to its ring-tip was carefully brushed away under cool running water. Under the running water, also, a trimmed feather was introduced into the cannula and the tube to push out the plasticine and to wash out the blood. Wire, cannula and tube were then dropped into a beaker receiving running hot water (about 80° C.) and there allowed to remain for about five minutes. On removal from this the parts were shaken free from water, passed through 95 per cent alcohol and again shaken free, passed through ether and let dry. By having a half-dozen cannulas and wires of standard size, it was possible to save trouble by cleaning a number at one time. Not infrequently the first few samples of blood taken from an animal showed rapid or somewhat irregular rates of clotting. Some causes for these initial variations will be presented in following pages. The fairly uniform rate of clotting in any individual after the initial stage, varied in twenty-one different animals from an average of 3 to an average of 10.6 minutes, with a combined average of 5.9 minutes. The conditions for these variations among the individuals have not been wholly determined. The Effects of Subcutaneous Injections of Adrenin The first observations were of this class. Oct. 27. A cat weighing about 3 kilos was given 3 cubic centimeters of adrenin 1:1,000, i. e., 1 milligram per kilo, under the skin. The animal, in this instance, was kept in uniform ether anesthesia. Following is a record showing when blood was taken, and the coagulation time in each instance: 2.56--Injection made .59--6 minutes 3.07--5.5 “ .13--5 “ .20--6.5 “ --- Average 5.7 minutes 3.27--3.5 minutes .44--2 “ .55--2.5 “ 4.07--3 “ .20--2 “ --- Average 2.6 minutes 4.44--6 minutes 5.00--4.5 “ 5.50--5 “ --- Average 5.2 minutes