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QUARTERLY JOURNAL

OF THE

STATISTICAL SOCIETY OF LONDON.

MARCH, 1851.

Vital Statistics of Iceland. By P. A. SCHLEISNER, M.D., &c.*

[Read before the Statistical Society of London, 18th November, 1849.]

In order to compute or compare the mortality in two different countries, where the calculation cannot be founded on long periods of years, it is necessary to have regard to the character of the periods used for calculation, especially in what concerns the different frequency of epidemical diseases. The life-table computed for Denmark by Professor Fenger is founded on the period 1835-44, which was a very favourable one, and free from any important epidemic. But if we look over the annual lists of deaths for Iceland, we shall soon discover that there is not a single quinquennium during which one or more severe epidemical diseases have not prevailed. The quinquennium 1840-45 is the most favourable in that point of view; but the year 1843 is marked by an epidemic of influenza, which prevailed in the middle of the year for two months, and almost doubled the_number of deaths for the whole year. I have, nevertheless, used that quinquennium for my computation; but, in doing so, I have eliminated the year 1843 out of the calculation, and have used the returns for the years 1841, 1842, 1844, and 1845, for the average number of deaths at different ages.

The average numbers of the living at the same ages have been obtained from the censuses for 1840 and 1845. My table is constructed in the same manner as Fenger's, and in computing the decrement column (the second), I have used the same formula of correction as he (vide "Det Kongelige Medicinsk Selskabs Skrifter," bd. 1, 1848, p. 30). The two tables can therefore be compared, and I will here give the results:

* Island undersögt fra et largevidenskabeligt Synspunkt af. P. A. Schleisner, Dr. Med., Medlem, 1849. This work contains the tables in detail from which the results in the paper are deduced.

VOL. XIV. PART I.

B

* For the ages 1-3 and 3-5 the quotients in Fenger's table are computed in another way than in mine, and may be compared for these ages with the double of my quotients (vide 1. c.).

The table for Iceland has, as above mentioned, been constructed in such a way, that the Icelandic.population can be compared under the same conditions as the Danish. The table will therefore show the peculiarities attributable to the Icelanders' constitution and manner of living. It will be seen that the same laws of mortality prevail in Iceland as in Denmark, except that the mortality, even under the same favourable conditions, is much higher in Iceland. This observation, however, applies especially to the first year of life; in other

words, the highest degree of mortality in Iceland is a little earlier than in Denmark.

It will further be seen, that the mortality of females in comparison with that of males is still more favourable in Iceland than in Denmark; the reason of which I have explained in my book. The probable lifetime at birth is, in Denmark, for males, 47 years, for females, 50; in Iceland, for males, 37 years, for females, 48. But this is not the true expression for the mortality of the Icelandic population, inasmuch as epidemics have been put out of the calculation.

In Denmark, severe epidemic diseases occur very seldom; but in Iceland, they are of very frequent occurrence. In order to find the true term for the Icelandic mortality, it will therefore be necessary to take a long series of years, taking no notice of the epidemics. But here again we encounter the inconvenience, that for the earlier years the census is taken so rarely, and the annual deaths are given so little in detail, as to render the construction of a correct life-table impossible. There is, however, one circumstance stated in the Icelandic returns which makes it possible to calculate the true mortality of the Icelandic population. The lists contain, besides the whole yearly number of births and deaths, the yearly number of those who have been confirmed. Now, in Iceland, the age of confirmation (this act being there, as in Denmark, a compulsory one) has always been very constant, between 14 and 15 years.

I have availed myself of this circumstance. Starting from the year 1750, I have summed up the number of births in every quinquennial period, and have computed how many of them in every fourteen years following the quinquennium have been confirmed. In that way I have found, that, during the last century, out of 1,000 children born, 548.3, on an average, have been confirmed, i. e., attained the end of 14 years; for this century, 583'6; and for the whole series of years, 569.5. This gives an enormous difference in comparison with the Danish population; for while at present, in Denmark, of 1,000 males born, 569 attain the end of 38 years; and of 1,000 females, 569 attain that of 41; in Iceland, the same number of both sexes attain only the end of 14 years.

The cause of this extraordinary mortality amongst the Icelanders may, as already suggested, be found in the frequency of epidemic diseases, of which the severity may be traced to the bad sanitary conditions of the country. As no country in Europe is afflicted in such a degree by epidemics, I shall explain this matter a little more fully, referring for further details to my book (p. 41, ff.) The Icelandic epidemics are of two kinds, partly native, that is to say, originating in the country itself, and partly foreign, that is to say, from time to time imported into the country by ships. To the first class belong typhus and influenza, which are the most frequent.

Typhus fever prevails almost every year; it does not differ from common typhus; but, besides this, there is another typhus-like fever, occasioned by famine, which has almost always followed the large volcanic eruptions, or the years of distress that from time to time have attacked Iceland.

Influenza shows in Iceland two different characters. It is either benignant, having no great influence upon the mortality, and in that