I have heard that a former distinguished President of this Institute once publicly stated that “Doctors rush in where Actuaries fear to tread.” It is also said that “at forty a man is either a physician or a fool”: but the presidential saying seems to suggest that a man may be both. With such a warning ringing in my ears, I yet venture to read before this learned Institute a paper on a thorny subject. I am doing so, first because that subject can be dealt with only by the united labour of actuaries and doctors; and second, because I am sure of the consideration and forbearance of the Fellows in any matters wherein I travel with halting gait.