On the fruitfulness of marriages.

as 4 to 3, or 12 to 10, which is a tolerably fast rate of increase.

Three causes appear to operate in producing an excess of the births above the deaths, 1. the prolificness of marriages; 2. the proportion of the born which lives to marry, and 3. the earliness of these marriages compared with the expectation of life, or the shortness of a generation by marriage and birth, compared with the passing away of a generation by death. This latter cause Dr. Price seems to have omitted to consider. For though he very justly says, that the rate of increase, supposing the prolific powers the same, depends upon the encouragement to marriage and the expectation of a child just born; yet in explaining himself, he seems to consider an increase in the expectation of life, merely as it affects the increase of the number of persons who reach maturity and marry, and not as it affects, besides, the distance between the age of marriage and the age of death. But it is evident that if there be any principle of increase, that is, if one marriage in the present generation yields more than one in the next, including second and third marriages, the quicker these generations are repeated, compared with the passing

away

On the fruitfulness of marriages.

of a generation by death, the more rapid will be the increase.

A favorable change in either of these three causes the other two remaining the same, will clearly produce an effect upon population, and occasion a greater excess of the births above the deaths in the registers. With regard to the two first causes, though an increase in either of them will produce the same kind of effect on the propor tion of births to deaths, yet their effects on the proportion of marriages to births will be in opposite directions. The greater is the prolificness of marriages the greater will be the proportion of births to marriages, and the greater is the number of the born which lives to be married, the less will be the proportion of births to marriages.

Con

Dr. Price himself has insisted strongly upon this, (vol. i. p. 270, 4th edit.) and yet he says, (p. 275.) that healthfulness and prolificness are probably causes of increase seldom separated, and refers to registers of births and weddings as a proof of it. But though these causes may undoubtedly exist together, yet if Dr. Price's reasoning be just, such coexistence cannot possibly be inferred from the lists of births and weddings. Indeed the two countries, Sweden and France, to the registers of which he refers as showing the prolificness of their marriages, are known to be by no means remarkably healthy; and the registers of towns to which he alludes, though they

On the fruitfulness of marriages.

sequently if within certain limits, the prolificness of marriages and the number of the born living to marry increase at the same time, the proportion of births to marriages in the registers may still remain unaltered. And this is the reason why the registers of different countries with respect to births and marriages are often found the same under very different rates of increase.

The proportion of births to marriages, indeed, forms no criterion whatever, by which to judge of the rate of increase. The population of a country may be stationary or declining with a proportion as 5 to 1, and may be increasing with some rapidity with a proportion as 4 to 1. But given the

may show as he intends, a want of prolificness, yet according to his previous reasoning show at the same time great healthiness, and therefore ought not to be produced as a proof of the absence of both. The general fact that Dr. Price wishes to establish may still remain true, that country situations are both more healthy and more prolific than towns; but this fact certainly cannot be inferred merely from lists of births and marriages. With regard to the different countries of Europe, it will generally be found, that those are the most healthy which are the least prolific, and those the most prolific which are the least healthy. The earlier age of marriage in unhealthy coun tries is the obvious reason of this fact.

On the fruitfulness of marriages.

rate of increase which may be obtained from other sources, it is clearly desirable to find in the registers a small, rather than a large proportion of births to marriages; because the smaller this proportion is, the greater must be the proportion of the born which lives to marry, and of course the more healthy must be the country.

Crome1 observes that when the marriages of a country yield less than 4 births, the population is in a very precarious state, and he estimates the prolificness of marriages by the proportion of yearly births to marriages. If this observation were just, the population of many countries of Europe would be in a precarious state, as in many countries the proportion of births to marriages in the registers is rather below than above 4 to 1. It has been shown in what manner this proportion in the registers should be corrected in order to make it a just representation of the prolificness of marriages, and if a large part of the born live to marry, and the age of marriage be considerably earlier than the expectation of life, such a proportion in the registers is by no means inconsistent with a rapid increase. In Russia it has appeared

' Ueber die Bevolkerung der Europais. Staat. p. 91.

On the fruitfulness of marriages.

that the proportion of births to marriages is less than 4 to 1, and yet its population increases faster than that of any other nation in Europe. In England the population increases more rapidly than in France, and yet in England the proportion of births to marriages, when allowance has been made for omissions, is about 4 to 1, in France 4 to 1. To occasion so rapid a progress as that which has taken place in America, it will indeed be necessary that all the causes of increase should be called into action; and if the prolificness of marriages be very great, the proportion of births to marriages will certainly be above 4 to 1; but in all ordinary cases, where the whole power of procreation has ' not room to expand itself, it is surely better that the actual increase should arise from that degree of healthiness in the early stages of life, which causes a great proportion of the born to live to maturity and to marry, than from a great degree of prolificness accompanied by a great mortality. And consequently in all ordinary cases, a proportion of births to marriages as 4 or less than 4 to 1 cannot be considered as an unfavorable sign.

It should be observed that it does not follow that the marriages of a country are early, or that vol. ii.