The result of Quetelet's researches on this subject, published in 1824 in the Nouveaux Mémoires de l'Académie de Bruxelles, is that the numbers of births and of deaths increase and decrease alternately, attaining their maximum towards the month of January in the case of deaths, and towards the month of February in the case of births, and their minimum about six months later-namely, in July. The maximum of births in February pre-supposes the maximum of conceptions in May, when the vital powers regain all their activity after the rigors of winter.

According to M. Villermé,1 the same holds good, mutatis mutandis, for Buénos Ayres, in the southern hemisphere. In Ireland, in the five years ending 1873, the average annual number of births was 148,211. Of these, 80,186, or 54′1 per cent., took place in the first six months, and only 68,025, or 45.8 per cent., in the last six months. In the quarter ending March 31, 40,015 births were registered; in that ending June 30, 40,171; in that ending September 30, 34,061; and in that ending December 31, 33,964. The equivalent annual rates per 1,000 of the estimated population were, for the whole year, 27.5; first quarter, 29-7; second quarter, 29.8; third quarter, 25.3; fourth quarter, 25.2.

(6.) Influence of Hours of the Day.-Several statisticians have investigated this curious subject. From observations extending over a long series of years at the Maternité de l'Hôpital Saint Pierre de Bruxelles, Quetelet estimates that 126 children are born at night for 100 born during the day; that is, 5 by night for 4 by day. Dr. Buek, of Hamburg, finds that of 1,000 children, 312 are on the average born between midnight and 6 a.m.; 249 between 6 a.m. and noon; 183 between noon and 6 p.m., and 256 between 6 p.m. and midnight. These numbers give the ratio of 131 births by night to 100 by day.

(7.) Influence of Professions, etc.—On this point we possess no satisfactory information. M. Benoiston says it may be laid down as a law that the population of States is always proportional to their producing power as regards the

1 Annales d'Hygiène. Quoted by Quetelet.

necessaries of life. A high birth-rate is consequently never observed amongst a poor and oppressed people, without agricultural pursuits, industry, and liberty. It is a wellknown fact that at San Domingo, in 1788, three marriages produced only two children amongst the blacks, while each marriage gave three children amongst the white population. To the same principle we may attribute the gradual extinction of aboriginal races, like those of Australia and North America. In 1865 only six of the aborigines of Tasmania survived, and no children had been born among them for many years.

(8.) Influence of Morality.—The number of conceptions is diminished by concubinage, as is exemplified in the barrenness of prostitutes, by too early sexual intercourse, and by habits of order and prudence. These last tend to lessen the number of marriages, and so react on the birth-rate.

Speaking of this, Quetelet says :-"The great fecundity of Ireland has been cited in illustration of the effect exerted on fecundity by discouragement and imprudence." In the province of Guanaxuato, in Mexico, the annual birth-rate is 100 for every 1,608 of the population, and the deathrate 100 for every 1,970-an excessive mortality, an excessive birth-rate, and an excessive poverty being there united. "Many political economists," Quetelet observes, "have maintained with reason that the most efficacious method of preventing a superabundant population is to diffuse knowledge and sentiments of order and of prudence.”

Illegitimacy.-In 1871, 44,775 illegitimate births were registered in England, amounting to 5.6 per cent. of the total births registered. In the ten years, 1851-60, they averaged 6.5 per cent.; in the following ten years, 6·1 per cent., thus showing a steady and substantial decline. Mr. Babbage gives the proportions in several countries and places as follows:

1

1 A letter to the Right Hon. T. P. Courtenay.

France, for 1,000 legitimate, 69-7 illegitimate births.

On an average of many years, the ratio in Berlin has been 1 illegitimate for 7 legitimate births, or 143 illegitimate for 1,000 legitimate births.

(9.) Influence of Political and Religious Institutions.-The rapid increase of the population observed in England and the United States of America, of late years, affords striking evidence of the influence for good on a nation of material prosperity and of a wise and liberal Constitution. But it is only in the presence of such that an increased fecundity is to be looked on as a favourable sign in the history of a nation. When the means of supporting life are scanty, a high birthrate is immediately followed by an increased death-rate. An extreme instance of this has already been referred tonamely, the province of Guanaxuato, in Mexico.

M. Villermé1 shows that in almost all Roman Catholic countries the season of Lent lessens the number of conceptions.

Still-births. Although still-births have not hitherto been registered in the United Kingdom, medical statisticians are very generally of opinion that they should be so; and it is likely that, before long, the registration of children who have died before performing the act of respiration2-"les morts-nés, dont l'existence équivoques semble appartenir autant aux annales de la vie qu'à celles de la mort" 3-will be made compulsory by law. Statistical tables, based on returns of eight millions of births, show that the proportion of still

1 Annales d'Hygiène.

2 Taylor. Medical Jurisprudence. 1865. P. 946.
3 Quetelet. Loc. cit. P. 221.

born among legitimate children varies from 1 in 18 to 1 in 20 of all the births. At Berlin, the mean proportion, from 1758 to 1821, was 1 in 19.8 births. Dr. Casper1 thinks the number of still-born is proportionally greater in towns than in the country, and Quetelet says that this view is borne out by the statistics of West Flanders for the years 1827-1830 inclusive. The ratios were-for the towns, 1 still-birth in 20-4 births; for the country, 1 still-birth in 38-2 births.

The mortality among boys is greater than that among girls, in the proportion of 140 to 100, while (as we have seen) the total males to females born are only as 105 to 100. This is ascribed to the greater risk of injury to the large male head and brain during delivery. Of 2,597 still-born children in West Flanders, 1,517 were of the male sex, and 1,080 of the female sex-the ratio being 14:10, or, as above, 140:100. Of 4,032 still-born children in Berlin, 2,289 were males, and 1,743 females-the ratio being 131 to 100. At Amsterdam, the means of the years 1821-1832 inclusive, give 244 male still-born, and 186 female still-born-the ratio is 13 to 10, and 1 still-born for every 16.9 births. In Paris (1823-1832) the ratio of still-born boys to girls was 12.2 to 10. As regards the influence of season, Belgian and German statistics prove that the number of still-births is highest in winter and early spring. Illegitimacy causes a marked increase of still-births, the proportion being 1 in 8 or 10. In Göttingen, among legitimate children, there were 3 still-born to 100 births, and among illegitimate 15 to 100. In Berlin, the corresponding proportions were 5 to 100, and 15 to 100, respectively. Syphilis in the mother also increases the number of still-births. Quetelet says that, at Hamburg, of 18 illegitimate children of diseased prostitutes, 6 were dead-born, and in another house in the same city there were 11 still-births among 93 births. Still-births are much more numerous in first than in subsequent confinements.

1 Ueber die Sterblichkeit der Kinder in Berlin. 1825.

CHAPTER VII.

STATISTICS OF DEATHS.

Registration of Deaths-Census Enumerations-Death-rate, how expressed-Influence of Sex on Mortality, or Death-rate-Influence of Age; Law of Mortality; Demoivre's Hypothesis; Mean Duration of Life; Expectation of Life; Probable Duration of Life; Life-Tables; Willich's Formula for determining the Expectation of Life; Mortality of Children; Centenarianism-Influence of Place; Climatology; City Life as compared with Country Life; Physical Configuration of a Locality; Sanitary Conditions-Influence of Periods; Scarcity; War; Pestilence-Influence of Seasons; Effects of Cold and Heat-Influence of Hours of the Day; Professions, Mode of bringing up, &c.; Civil and Religious Institutions, &c.

In order to arrive at an accurate estimate of the birth-rate or of the death-rate of a population, it is necessary to have a complete system of registration of births and deaths, and, in addition, a correct enumeration, or census, of the population. Any deficiency in either the registration or the census will lead to erroneous estimates of the birth and death rates.

In England, Registration was introduced in 1836, by the Acts 6 & 7 Will. IV., c. 85 & 86, and on the 1st of July, 1837, the system was set working. Some idea of the work done since then may be gathered from the Registrar-General's Thirty-fourth Annual Report, in which this passage occurs :1.

"The records of this office, for the period of 34 years, extending from the middle of 1837 to the end of 1871, comprehend, in respect of their relation to the three great events of life-birth, marriage, and death-upwards of forty-seven million NAMES; each name being inscribed in an Alphabetical Index, prepared quarter by quarter promptly as the certified copies reach this office, and so arranged as to give the utmost facility for reference. All that is necessary on the part of an inquirer to ensure the immediate production of an entry of marriage, birth, or death, is that he should give the year in which the event took place, and the correct name of the person to whom it relates."

1 P. xx.