SIMPLE INTEREST AT VARIOUS RATES.

3 Pr. Ct. 31⁄2 Pr. Ct. 4 Pr. Ct. 41⁄2 Pr. Ct. 5 Pr. Ct. 6 Pr. Ct.

93 139

$0 50
100
150

80 54

$0 57 | $0 61

|

$0 64

$0 68 | $0 71 | $0 89

107

114

1 21

1 20

136

1 42

1 79

193

204

One dollar, from one year to fifteen years, with compound interest added semi

annually, at different rates.

COMPOUND INTEREST, TO AMOUNT TO $1,000 IN A DEFINITE

Explanation.-How much must be invested every year, at 41⁄2 per cent compound interest, so that the proceeds will amount to $1,000 in twenty-five years? Look under the heading "41⁄2 per cent," at the right of twenty-five years, and you find $21 47,

the answer, etc., etc.

LONGEVITY CALCULATIONS.

According to Buffon, the life of man "can" last six times as long as it takes him to become fully developed; according to Bacon and Hufiand, eight times as long. Now, since man is not considered in the anatomical sense completely mature before the twenty-fifth year of age his life, according to the last named two authorities, "could" last two hundred years. But, as a matter of fact, there is no record whatever of such long lives. Among the extraordinary cases of longevity on record and well attested is that of the Englishman Thomas Parr, who lived happily in Shropshire to the age of 152. The celebrated Harvey, who dissected him after death, found his body in excellent condition, and stated that had it not been for his intemperance he might have lived much longer. A census taken under Emperor Vespasian showed in the relatively small territory of Italy alone eighty persons over one hundred years old, and among these two who had reached the age of 140. The census of the United States for 1890 shows 3,981 centenarians and that for 1900 3,504 (males, 1,271; females, 2,333). These figures have only a dubious value, not merely because the vanity of old people in general causes them to claim their age much higher than it really is, but for the fact that the majority of these centenarians are ignorant persons (2,553 negroes, 111 Indians and 3 Mongolians), whose statements as to their age cannot be relied upon.

It has been calculated that of 1,000,000 men and women who have passed the age of 30 about one-half live to the age of 63, one-fourth to the age of 76, every tenth to the age of 83 and every hundredth to the age of 97 years. Of 1,000,000 only 100 attain the age of 100, 2 the age of 104, and to find a person only one year older 2,000,000 births have to occur; but only among 10,000,000 human beings one grows 106 years old.

The following tables show the expectation of life from various ages and the percentage living to the end of certain periods: American Experience Expectation of Life.

According to the American Experience Table of Mortality.

Per Cent Living at End of Period.

Per cent that live to the end of a term of years, according to the American

Experience Table of Mortality.

RELATION BETWEEN DEATH AND BIRTH.

An examination of the proportion between the death rate and birth rate in the various countries goes to show that there exists a relation between death and birth. Indeed, a comparison of the respective statistical tables reveals the fact that all fluctuations in the rates of births and deaths proceed in parallel lines, that is, that every increase in the death rate is infailibly accompanied by an increase of births, and, vice versa, every decrease in the death rate is followed by a decrease of births, so that, despite a few exceptional fluctuations, the excess of births remains approximately the same, at least with regard to European countries, where this parallel course of death and birth lines has been established in the various nations by statistical figures. They prove, for instance, that in the countries with a small death rate, e. g., where it does not exceed 18 in 1,000 inhabitants, the birth rate, too, is smaller than with other nations. England the proportion of death to birth is 16 to 28; in Scotland, 17 to 29; in Denmark and Norway, 15 to 29; in Sweden, 15 to 26; in Holland, 16 to 32; in Belgium, 17 to 28, and in Switzerland, 18 to 28. This shows a mean excess of births of 12 in 1.000.

In

It is interesting to observe how this average is also maintained by those countries whose death rate is higher, and which consequently also exhibit higher birth rates in order to keep up the normal excess. Thus Germany shows 20 deaths to 35 births; Austria, 24 to 36; Hungary, 26 to 37; Russia (1901), 32 to 42; Rumania, 25 to 39; Italy, 22 to 33; Spain, 26 to 35, and Portugal, 20 to 32. The historical comparison, too, shows the same parallelism in the rise and fall of the death and birth rates. In the years 1841-'50, for instance, England records 32.6 births against 22.4 deaths in 1,000 inhabitants; proportionately the number falls to 28.1 and 15.9 in the years 1901-'05. Germany in 1841-'50 counted in the average 25.8 deaths in 1,000 inhabitants against 36.1 births; in 1901-'05 the figures are 19.9 against 34.7. And similar are the proportions in Italy, Austria and Spain. With the exception of France Ireland is the only country that remains below the average excess of births of 12 in 1,000; against a death rate of 18 in 1,000 are only 23 births. France, however, occupies in this respect an exceptional position among the nations, recording as she does only 21 births against 20 deaths, so that the excess of births is only 1 in 1.000. According to the calculations of the French physician Dr. Ox, from whose statistical tables the above figures are borrowed, 468,000 more children would have to be born annually in France if the French nation is to keep equal step with the other European states.

PROPORTION BETWEEN THE SEXES.

Statistics show that the proportion between the sexes of the new born is 106.3 boys to 100 girls. Boys are therefore considerably in excess at birth, the male majority amounting to 63,000 in every million human beings. This seems to contradict the general observatior to the effect that women are in the majority. This contradiction is, however, explained by the fact that the proporion at birth does not remain stationary, but is reversed in the later years of life. Until the age of ten there is still an excess of boys, but from the age of ten to twenty the proportion between the sexes slowly adjusts itself, and in the third decade of life the proportion becomes 100 males to 102.7 females. This excess of females grows continually, so that at the age of seventy the proportion becomes 100 males to 122.3 females. According to Professor Wilcox, of Cornell University, who has figured out the proportion of sexes in the United States for the census of 1900, there are found in Continental United States 1,638,321 more males than females, or about two more males than females in every 100 of population. Among the negroes there are a few more females than males, while among the Indians there is also an excess of males.

DIFFERENCE OF MEASUREMENTS IN MAN AND WOMAN.

One of the most striking differences between man and woman is to be found in the stature, which already begins at birth. Measurements made on a great number of children go to show that the new born boy is, on the average, one-half to one centimetre taller than the new born girl. Numerous measurements made of adults show a mean difference of 10 to 12 centimetres in favor of man. Also, man's weight is, on the average, more considerable than woman's. The mean weight of new born boys is 3,333 grams, and of new born girls 3,200 grams, the difference in favor of the boys being, therefore, 133 grams. The difference increases in the adult, as the mean weight of the adult female is about 55 kilograms and of the adult male 65 kilograms. It is also to be noted that the total weight of muscular tissue in the adult vigorous woman hardly constitutes one-third of the weight of her body, while in the adult vigorous man it is, on the average, above one-third of the weight of the body. In woman the greater accumulation of adipose tissue causes her form to be softer and rounder, but at the same time rather prevents than favors the development of muscular tissue.

Besides the generally known differences in the size of hand and foot, it is interesting to note that woman, as shown by Ecker and Montegazza, has her index finger frequently longer than her ring finger, while with man the ring finger is the longer, which brings him nearer to the negro and anthropomorphous ape. As a rule, it is not difficult to distinguish in the so-called Caucasian race the skulls of men from those of women. Women's skulls are decidedly smaller. According to Topinard, the mean size of 347 European male skulls is 1,560 cubic centimetres and of 232 female skulls 1,375 cubic centimetres, showing a difference of nearly 200 cubic centimetres 'n favor of man. Eighty-three male African negroes had a mean capacity of 1,405 cubic centimetres, and 32 skulls of African negro women a capacity of 1,250 cubic centimetres, therefore a difference of about 150 cubic centimetres. Forty-four male skulls from the stone age had a capacity of 1,600 cubic centimetres; 28 female skulls of the same epoch 1,410 cubic centimetres; hence the same difference as with the negroes. In proportion to the inferior skull capacity in woman is, of course, the inferior brain mass and brain weight found in woman. Numerous measurings and weighings made by Bischoff, Manouvrier, Topinard and others go to show that the average weight of he brain of man is 1,372 grams and of woman 1,231 grams; hence a difference of 141 grams. In the new born the difference is less, amounting, according to Mies, to about 10 grams in favor of boys. If, however, we consider the proportion of the brain weight to the total weight of the body, we find a small difference in favor of womanthat is to say, relatively to the weight of her body, woman has a heavier brain.

There exists also in the very new born a striking difference in the formation as well as in the development of the brains of boys and girls, so that the respective brains can at once be distinguished one from the other. The male brain develops especially in the frontal and parietal lobes more rapidly and considerably than woman's. This is important, in view of the fact that it is the frontal cavity to which is ascribed the most important part in the performance of the so-called intellectual functions. Other minor differences consist in the hairiness and the development of the thyroid gland, which, as a rule, is greater, and of the larynx, the heart and the lungs, which generally are considerably smaller in woman than in man. It is a striking fact that man has a great number more of red blood globules than woman, and this is so not merely on account of his having a larger quantity of blood but also if the quantity of blood is reckoned the same. Expressed in round figures, man has in one cubic millimetre of blood 5,000,000 red globules, woman only 4,500,000. Also, the specific weight of the feminine blood is inferior. As the red blood globules carry to the tissues of the body the oxygen so necessary to life, the Importance of this difference between the sexes is at once evident.