EFFECTS OF MECHANICAL AGITATION AND OF TEMPERATURE UPON COMPLEMENT.

1. Under certain conditions, mechanical agitation destroys the complementary activity of guinea pig serum. It is most injurious when carried out constantly at a temperature of 37 degrees C., but it is extremely insignificant at 10 degrees C. After the first few hours at 37 degrees C., the destruction of complement proceeded much more rapidly, and after six hours it was almost complete. On the other hand, within one hour shaking had almost no destructive effect on complement, even at 37 degrees C. From this we may conclude that the several shakings which are necessary for fixation experiments during incubation do not modify perceptibly the outcome of the reactions. 2. The rate of destruction of the complement of guinea pig serum at temperatures above 45 degrees C. is progressively greater as it approaches 55 degrees C., at which temperature the activity is reduced in thirty minutes to one-thirtieth to one-fortieth of the original strength of the unheated serum; but it is not completely destroyed, as is commonly assumed. The velocity of destruction of guinea pig complement when exposed to 55 degrees C. for various lengths of time is found to be quite irregular, and not proportional to the length of time. This irregularity, however, presents a certain rhythm, a period of greater destruction alternating with one of less destruction.