The lives which present themselves for assurance are, in the process of selection, divided into three main groups or classes:—

I. Lives insurable at the ordinary rate.

II. Lives insurable only at extra rates.

III. Uninsurable lives.

Although, in measuring what we call “extra risk,” only the subdivisions of Class II. are of practical significance, yet each of the three classes admits of almost indefinite subdivision in respect of the quality of the lives embraced in it.

In the first class, some lives present no flaw of any kind in health, physical condition, occupation, or family history; others, at the further end of the scale, present flaws which bring them close to the border line of Class II.; and between those two extremes there is every degree of variation. Using terms that are not unfamiliar, Class I. may be subdivided into three distinct groups:—

(a) Unexceptionable lives, presenting no unfavourable feature.

(b) Good average lives, in which the personal or family history, or the physical condition, is not entirely faultless, but which present no feature likely to tell against the life-prospects.

(c) Fair average lives, presenting some flaw or imperfection, or some combination of unfavourable circumstances, which only falls short of requiring an extra premium.