plethora in him. There is, then, nothing improbable in the affirmation that the organization of man may endure and his vital force act during two centuries." Dr. Berthelot, adopting the doctrine that the duration of human life is proportioned to the time required for reaching maturity, cites as a well-known fact that the traveler Delahaye, who was born with a robust constitution and led a regular life, was not matured till long after the common time, married and became a father at seventy, and lived till he was a hundred and twenty years old.
The German physiologists have paid the greatest attention to this subject. Haller maintained that man might live to two hundred years. Hufeland, in his "Art of prolonging Life," teaches that the age of the world has to this day had no influence on the duration of human life, and that it may be prolonged to the length of the lives of the patriarchs computed according to the actual divisions of time; assuming that the animal lives eight times as long as it takes it to reach maturity, he calculates that man becoming an adult at twenty-five years, should live to be two hundred years old. This opinion is shared by Professor Karup, Dr. Buschner, of Darmstadt, and others who have written with reference to life insurance. Dr. Gardner, an English physiologist, has also published a work on the means of prolonging life, and has likewise adopted the doctrine of a ratio of the whole duration to the period required for full development. He believes, however, that the latter period is not fixed, but that it varies from eighteen to twenty-one years, and consequently the whole length of life should be between ninety and one hundred and five years. But he does not hesitate to affirm that the latter age has never been passed, if it has been reached. Sir George Cornewall Lewis is still more skeptical, and does not believe that the existence even of a centenarian can be demonstrated. Mr. J. Thomes, in "Notes and Queries," while he contests ultra-centenarianism as impossible, cites as entirely authentic the fact of a client of an English life-assurance company having died in 1879, at the proved age of one hundred and two years and some months. But this case, he adds, "is the only one which an open inquiry among the oldest life-assurance companies of England has brought to light." According to Mr. Thompson, however ("Curiosities of Longevity"), nothing decisive is involved in the extreme rarity of centenarians in the annals of insurance companies, for the highest ages are found in the lower classes of society, and notably among agriculturists, who do not insure their lives.
So far as to doctrines; we now come to examine the facts. In this we must exercise considerable restraint, for the data we have personally gathered and those which we have found in books, memoirs, medical dictionaries, etc., form a considerable collection, the reproduction of which would require a volume; we shall have to make a very limited choice from among the numerous documents.
The ancient Greek writers, especially Lucian, have left biographi-
