M. Lagneau studied this question with particular reference to France. He came to the conclusion that the conditions of life are not sufficient to explain the differences which were proved by his investigations, and that the age of puberty, depending upon the rapidity of the development of the organism, varies slightly with the race. This opinion, which it seems as if we might accept within the limits he himself has prescribed, M. Lagneau states with great reserve.
These limits are very narrow. They vary from fourteen years and five days to sixteen years, one month and twenty-four days. The minimum age is presented by the female population of Toulon: the maximum, by that of Strasbourg. But between these two localities there is a difference of about three degrees of latitude and five degrees in the mean temperature. Toulon enjoys a very equable climate; the climate of Strasbourg is, on the contrary, excessive; at Toulon the climate is sunny, while at Strasbourg there is much cloud; the Toulonaise lives in the open air, and breathes the stimulating air of the sea, the Strasbourgeoise lives in the house and breathes an air which is generally damp; the former drinks wine, the latter beer. All these conditions, stimulating on the one hand, and debilitating on the other, must exercise some influence. After taking all these circumstances into consideration, we see that, in France at least, the influence of race scarcely exceeds that exercised by difference in social position upon the population of the same town.
The researches of M. Lagneau also have reference to the time when, both in the male and in the female, the reproductive faculties become extinct. The evidences are here neither so numerous nor so definite. Nevertheless, from the little that we know on this point, the result would seem to point to conclusions similar to those which we have mentioned above.
VIII. We might easily be led to think that forwardness or backwardness in organic development, defined by the age at which puberty appears, should involve a proportionately longer or shorter duration of human life. Precise observations are far from being so numerous and complete as to solve this important problem with any degree of certainty. The greater number of facts with which we are acquainted, scarcely seem, however, to support the theoretical conclusions admitted by some anthropologists, by Virey among others. Everything seems to indicate, on the contrary, that the limits of life are almost the same for all human races, provided that they are placed in conditions of existence, which are relatively equally favourable. It is, in fact, evident that these conditions exercise a most marked influence upon the duration of organisms. When life is in question we do not deny the action of the conditions of life.
Here, again, appears the multiple nature of these conditions. We find from the statistical researches of Boudin that in sixty-seven years, from 1776 to 1843, the average life of man in France was increased by eleven years. It has, therefore, gained sixty days a year; it has attained almost the highest limit gained in this respect by European peoples (34·45 years). The temperature has not changed, nor has there been any amelioration in the climate. But the general conditions of existence are modified and the result appears in these very significant figures.
The average life of European Whites, the only peoples concerning whom we possess sufficiently exact data, oscillates between 28·18 years (Prussia) and 39·8 years (Schleswig-Holstein, Lauenbourg); a difference of more than eleven years.
The tables of average duration of life, collected by Boudin and borrowed from Hain and Bernouilli, prove beyond a doubt that, amongst our European peoples at least, mean duration of life depends to a very slight extent, if at all, upon the race. The German states present an average of from 28·18 years (Prussia) to 36·8 years (Hanover).
Temperature, at least when considered alone, seems to exercise hardly any notable influence, Naples standing almost midway between the preceding numbers (31·65 years).
These facts, obtained from among the best known peoples, justify us in thinking that, other things being equal, the duration of life must be almost universally the same. It will be understood that all strict comparison is here out of the question, for want of statistical documents, properly so called. Still, a number of facts obtained by various travellers amongst peoples of very different races, and, in some cases, placed under opposite conditions of existence, seem to justify this conclusion.
All travellers, who have been in a position to judge for themselves, have spoken of the Lapps as generally living to a great age; men of from seventy to ninety years are not rare amongst them.