One of the most important branches of statistics is that which deals with the causes [unclear: of] death, and the Ages at which particular [unclear: diseas] exert their maximum or minimum force on [unclear: the] human organism, so far as the same has [unclear: been] evidenced by the termination of life.

It has been shown in a previous paper [unclear: that] the number of deaths recorded in this colony [unclear: for] the thirteen years—1880-92-was 77,234, [unclear: of] which 44,547 were males and 32,287 [unclear: females] and as these deaths had been employed [unclear: in] deducing the tables of New Zealand [unclear: mortali] it was intended to exhibit in some detail [unclear: th] causes thereof as set forth in the reports of [unclear: th] Registrar-General for the years mentioned. [unclear: But] on proceeding to summarise the deaths [unclear: is] accordance with their causes it was found that [unclear: is] change had been made in the system of [unclear: class] ficatiou in the year 1885, which involved [unclear: the] establishment of fresh classes and the [unclear: tran] ference of some diseases from one class [unclear: t] another. In consequence of this, and [unclear: becau] it seemed desirable in any summary of [unclear: fa] causes of death for a period of years, that [unclear: the] new classification should be adopted, it [unclear: was] resolved that instead of the thirteen [unclear: years]1880-92—the ten years during which the [unclear: nea] classification has been in force—viz., 1885-[unclear: 86] should be the period dealt with.

During this period it is found that the [unclear: number] of deaths of males was 36,358 and of [unclear: female]26,131—in ail 62,489. But as the mortality [unclear: and] causes of death vary with age, the [unclear: number] living and the deaths must be divided [unclear: into] certain number of corresponding groups [unclear: in] order to determine the death-rate and the [unclear: fath] diseases in each group.

In the reports of the Registrar-General [unclear: the] deaths under one year of age are divided [unclear: into] four periods—viz., under one month, one to three months, three to six months, and six to twelve months, and then the total is shown.

From one to five years the deaths are [unclear: give] for each year of age, and also the total [unclear: dying] under five years of age. From age [unclear: five to] eighty the deaths are given in [unclear: quinquen] age groups, fifteen in all. The deaths at [unclear: age] eighty and upwards are all grouped together then there is a column for deaths at ages [unclear: ng] specified, another for the total deaths at [unclear: fi] years and over, and lastly a column for [unclear: the] deaths at all ages—making a total of [unclear: twenty] nine columns. From this it will be seen [unclear: the] particulars relating to the ages at death [unclear: an] given with great fulness in the annual [unclear: reports] and the same remark applies to the causes [unclear: of] death.

In an article of this character, however, it [unclear: is] not necessary that the same number of [unclear: ag] groups should be maintained, as too [unclear: min] sub-division of the deaths and fatal [unclear: disease] would, from the smaller numbers [unclear: employed] affect the value of the rates deduced from [unclear: then] for comparative purposes. Moreover, as it [unclear: h] been found that the relative mortality of [unclear: the] two sexes from particular causes at many [unclear: age] differs considerably, and frequently throws [unclear: light] upon the fluctuations in the general [unclear: death] rates, it is desirable that the rates of [unclear: mortal] of males and of females should be [unclear: shown] separately, and this is an additional reason [unclear: for] reducing the number of age periods.

As all the authorities on sanitary science [unclear: a] of opinion that the death-rates of infants [unclear: under] one year, and of children under five year of page 9 [unclear: re] are more important than the rates at any [unclear: er] groups of ages, as tests of the sanitary [unclear: dition] of a community there was no hesi[unclear: tion] in retaining these two divisions.

For the next ten years (five to fifteen), which [unclear: ay] be designated the school age, and during [unclear: ich] the boys and girls are in most cases still [unclear: pendent] on the exertions of others for their [unclear: tenance], a third division was made.

The period between age fifteen and sixty-[unclear: e] has been called the supporting age, because, [unclear: eaking] generally, the majority of persons are [unclear: ble] to contribute largely to their own main-[unclear: ance], while between the ages of twenty one [unclear: sixty] they do more than support themselves. [unclear: t] as the rate of mortality increases greatly [unclear: the] latter half of this period of fifty years [unclear: has] been deemed desirable to sub-divide it [unclear: to] two periods of twenty-five years each—viz., [unclear: een] to forty and forty to sixty-five. After [unclear: ge] sixty-five we again reach what in general [unclear: rms] may be called a dependent age, and for [unclear: present] inquiry it has not been considered [unclear: essary] to exhibit any more divisions of the [unclear: ths] at ages sixty-five and upwards. The [unclear: ths] at all ages have, therefore, been arranged [unclear: six] groups of ages (with an additional column [unclear: deaths] at ages not specified), and are so set [unclear: arth] for each sex in Table I., which is appended [unclear: this] paper.

The same table shows also the causes of death [unclear: rranged] in classes and orders according to the [unclear: lassfication] now in use, with the number of [unclear: eaths] registered under each during the ten [unclear: ars]1885-94 and for the age groups already [unclear: tioned.]

For reasons which will be given later on it [unclear: not] intended to investigate the mortality from [unclear: ch] of the causes specified in the annual returns, [unclear: to] compare the deaths from each alleged [unclear: se] during one group of years with those in [unclear: ther], as many of such comparisons would be [unclear: but] little value, hence also it has not appeared [unclear: necessary] for us to exhibit in detail all the [unclear: gistered] causes of death, or the number of [unclear: ths] entered under each. The intention is to [unclear: trict] the observations mainly to the large [unclear: tural] groups or orders of disease, and to a [unclear: ited] number of specified diseases or causes [unclear: fatality] of distinctive character.

In pursuance of this arrangement the deaths [unclear: class] IV. (Constitutional Diseases)—which are [unclear: divided] into orders like most of the other [unclear: ge] classes—have been arranged in four [unclear: sions]. The first includes the deaths from [unclear: matic] fever, rheumatism and gout; the [unclear: ond], deaths from cancer or malignant dis-[unclear: the] third, deaths from phthisis and other [unclear: bercular] diseases; and the last, deaths from [unclear: betis] mellitus, anæmia, and other diseases [unclear: e] to a bad habit of body.

The alleged "causes of death," as given in [unclear: e] Registrar-general's returns from year to [unclear: ar], may, we believe, be taken as on the whole [unclear: fair] approximation to the truth. At the same [unclear: me], it is necessary to remember that these [unclear: tistics] are liable to various kinds of imper-[unclear: tions,] and should be used with caution.

[unclear: In] the first place, white the number of deaths [unclear: ere] no cause at all is specified is small, there [unclear: a] considerable number in which the cause is [unclear: ted] so inadequately that they could not be [unclear: ferred] to any definite disease or class. Daring [unclear: ten] years under review there were 3026 [unclear: ths] of this character (viz., 1667 males and [unclear: se] females), being 4.84 per cent, of all the [unclear: ths] registered for the period.

In the second place, when a definite cause if [unclear: ren], there is reason to believe that in a number [unclear: cases] doubts may be entertained as to its [unclear: ing] strictly accurate. Only a portion of the [unclear: ple]. when stricken down with sickness or dis-[unclear: can] be visited regularly (through long illnesses, perhaps) by skilful surgeons or able physicians, so as to afford opportunities for the cause of death being determined and recorded with scientific accuracy. In the remote and sparsely populated parts of the colony, the people, if not entirely beyond the reach of a duly qualified medical practitioner, can be seen by him but seldom, and, as has been well said by an able medical statist, "He who sees only the end of a case, however skilled in diagnosis or versed in pathological inquiry, cannot always venture to certify on vague report or even shrewd suspicion, the primary or secondary cause when he has positive evidence only of the tertiary or last stage, e.g., the dropsy, or abscess, or hæmorrhage, or mortification, which was the proximate cause of death." The same writer also makes the following remarks on another practical difficulty of our certifiers of death;—"In any statistical analysis of deaths based on certified causes, only one cause can be assigned to each event, and in a large class of cases insuperable difficulties must arise in selecting that phase or stage of morbid action, that particular vital or structural change, which is to be formally returned as the cause of death. Among a number of reporters of various degrees of capacity and information, though all may be legally qualified practitioners, there can be no possible guarantee that all should adopt the same principle of selection."

Another source of imperfection in the returns arises from the fact that in some cases the medical attendant may, from a desire to spare the feelings of relations or other motive, be less explicit in the statement of the cause than the facts within his knowledge would warrant.

In the third place, it has been stated by more than one medical statist, as well as by the Registrar-general of England, that in comparing the mortality from specified causes in successive years, allowances have to be made for the changing fashion of medical nomenclature. The last-named authority says :—"There are times, for instance, when the ordinary medical attendant designates all deaths from vaguely diagnosed affections of the respiratory organs as bronchitis, and other times when he prefers to designate all as pneumonia." Having regard to these various kinds of imperfections in the data, as well as others that could be mentioned,^* it seems reasonable to conclude that for purposes of comparison more reliable results will be obtained when the deaths from groups of diseases are taken together, such as diseases of the nervous system, or diseases of the respiratory organs, rather than from the deaths from single specified causes of no very decided form.

Before entering further into the subject of the causes of death it may be of interest to notice that in the ten years under review close on one quarter of the males, and nearly three-elevenths of the females who died were under one year of age; that nearly one-fourth of the males and over three-tenths of the females were between five and forty years of age; that over three-elevenths of the males, but less than one-fifth of the females, were between forty and sixty-five years of age; and that over one-seventh of the males, and more than two-fifteenths of the females, were over sixty-five years of age. This is what has been, but owing to the increasing proportion of elderly people in the population, these proportions will vary, and increases may be expected at the higher ages. The exact figures are as follows :—

The registered deaths from specified causes may be viewed in three aspects—first, in relation to the total deaths from all causes either at all ages, or at groups of ages; second, in relation to the ages at which the deaths from the specified cause takes place—that is, whether the greatest mortality takes place in infancy, youth, man-hood, or old age; and third, in relation to the number living either at all ages (which yields what is known as the general death rate) or at groups of ages, All these views are of interest and value, but not in equal proportions; the comparison of the deaths from specified causes at groups of ages with the population living at the same groups of ages being by far the most valuable of the three, and, it may be added, the most difficult of determination. Our remarks on the two first aspects will therefore be brief.

We would now direct attention to Table II., which shows the proportion of deaths from various causes to 100 deaths from all causes, first, at all ages, and then at six groups of ages.

At all ages it is found that the most fatal causes are diseases of the respiratory and nervous systems (i.e., lung and brain diseases), accidents, tubercular diseases, and diseases of the digestive organs, in respect of males; and diseases of the respiratory, nervous, and digestive systems, tubercular, miasmatic, and developmental diseases, in respect of females : over one-half of the deaths being due to the causes named—viz., males 63 41 per cent., females 54.29 per cent. With the addition of miasmatic and developmental diseases to the male proportion, and circulatory and diarrhœal diseases to the female, the causation of three-fourth s of the deaths is obtained.

In the case of infants under one year of age 14.25 per cent. of the male deaths, and 15.74 per cent. of the female, are ill defined or not specified, while of the alleged causes of mortality, developmental, diarrheal, respiratory, and digestive diseases are the chief; 57.32 per cent. of the male deaths, and 56.17 per cent. of the female, being registered against the diseases named.

When we come to the deaths under five years of age (which includes those under one year) considerable variations are found in the proportions from the specified causes. The proportion of ill-defined is reduced to 11.11 per cent. in the case of males, and 11.99 per cent. in the case of females. On the other hand, the proportion from lung diseases has increased to 16.42 per cent for males, and 15.55 per cent. for females. Next in order of fatality come diarrhœal, digestive, miasmatic and nervous diseases ranging from 13.23 to 10.26 per cent, for males, and 13.48 to 10.13 per cent. for females, and bringing the total up to close on 76 per cent. of the whole deaths in this group.

At the age group 5 to 15, it will be seen that in respect of males miasmatic diseases are page 10 accountable for close on 23 per cent, of the deaths, while close on 21 per cent. are due to accidente; diseases of the respiratory and nervous systems account for 23.61 per cent. and tubercular diseases for 9.23, making a total of 76.53 per cent, of the deaths in this group. In respect of females, miasmatic diseases are the most fatal. the rate being 30.26 per cent. Tubercular diseases come next, but are a long: way after, the rate being 14.32 per cent.; then respiratory disease, the rate being 14.11, So that these three causes are responsible for 58.69 per cent., of all the deaths in this age group. It will be noticed that the mortality from miasmatic and developmental diseases, diseases of the digestive system and ill-defined causes show a great reduction upon previous percentages for both sexes. On the other hand, there is a considerable increase in the proportion on deaths from rheumatic fever, &c., as well as diseases of the circulatory system.

At the age group 15 to 40, and in respect of mules, it will be seen that tubercular diseases are the most fatal cause of death, the rate being 27.76 per cent.; accidents come next, 22.07 per cent, or, including suicides and other violent deaths, 25.22 per cent. In other words, to these two causes more than half the deaths at this age period are due, so that of twelve deaths between the ages of 15 and 40, three are likely to be caused by tubercular disease, and three by violence. Such a waste of manhood in its prime by violence is greatly to be deplored, and emphasises the need of all proper precautions being taken wherever possible to reduce it. In regard to females, tubercular diseases are the most fatal, close on thirty-one deaths in every hundred being due to them. Diseases of the reproductive system are now at. the maximum, the rate being 11.54 per cent, Miasmatic diseases come next, followed by diseases of the respiratory, digestive, nervous, and circulatory systems, the rate ranging from 8.24 per cent. to 6.24.

At ages 40 to 65 the percentage of deaths from a majority of the causes do not differ greatly between the sexes, with the exception of deaths from violence and cancer. In regard to the first, the rate for males is 10 per cent., and for females 3.41; in regard to cancer the rate for females is 17 02 per cent., and for males 9.81. The percentage of deaths from miasmatic and tubercular diseases show a considerable reduction but, on the other hand, large increases are exhibited in diseases of the nervous, circulatory, respiratory, digestive, and urinary systems, so that 54.22 per cent, of the male deaths, and 58.88 of the female, are registered as caused by the class of diseases known as local.

At the last group of ages, 65 and upwards, the proportion of deaths alleged to be due to old age is 21.44 per cent. in respect of males, and 27.44 in respect of females. But old age" is an ambiguous designation as a "cause" of death, and there is reason to believe that a more careful observance of the diseases of the aged would result in the deaths from this alleged cause being greatly reduced. Diseases of the nervous, circulatory, and respiratory systems come next in order of fatality, the proportion due to these three being 44.31 per cent. in the case of males, and 44-03 per cent, in that of females. Cancer, it will be seen, claims almost the same proportion of males as females in this age group, say 7½ per cent.

Before quitting this part of the subject, it may be of interest to compare the percentages of deaths from each class in this colony with what has been experienced elsewhere, and in the following table a comparison is made between the rates in New Zealand, New South Wales, and England and Wales, at two groups of ages—viz., under and over five years, and for both sexes.