In a report on the results of an investigation of the mortality experience of life annuitants (J.I.A., vol. liv, pp. 43–90), it was pointed out that selection may be divided into “temporary selection” and “class selection.” We felt that there were two forces operating at the moment of entry or selection—(a) an initial selection based on the state of health at the time, (b) a permanent force operating throughout the whole of the after lifetime, due to the class of lives involved. The special investigation then made showed that force (a) soon worked itself out, hence the expression temporary selection; force (b) was doubtless also initial since it came into operation at entry, but it appeared to be permanent from the fact that the mortality remained light practically until the limit of life. Although the present note is the outcome of that investigation, it is not proposed to confine it to annuitants but to consider it in its bearing upon any mortality experience.