In a paper read before this Institute many years ago, by Mr. S. Brown, occur the following judicious remarks relative to Statistics of Mortality and Sickness:—

“It has frequently been remarked” says Mr. Brown, “that “however varied and uncertain may be the occurrence of the events “to which the life of a single individual is exposed, the average “return in a large mass of persons is so regular as to be predicted “with confidence within very small limits of error. On the “uniform happening of these events under similar circumstances, “or the discovery of the laws by which they are governed, the “actuary depends for the application of the theories of probabilities “to the many useful purposes for which they may be rendered “available. The principal difficulty which he has to encounter is “the indefinite character of the event itself. In endeavouring to “ascertain the law of mortality at any period of time, or in any “particular country, the event is certain and definite whenever it “does occur. The attention is only required to the difference of “the circumstances which cause it—the age of the party, the “nature of the disease, or the locality within certain boundaries of “which a greater or less intensity of disease may prevail. But a “much greater difficulty arises when the event itself which is under “observation is of an uncertain character; such for instance as the “average duration or effects of sickness in a large number of cases.