INFLUENCE OF ORDER OF BIRTH, ETC. 311 
Closely associated with the effect of order of birth upon off- 
spring is the problem of the influence of parental age. This topic 
has received more or less attention from the time of Aristotle to 
the present. Various opinions have been put forth with a degree 
of confidence which is often in inverse proportions to the ade- 
quacy of the evidence upon which they were based. The subject 
is more difficult than appears upon the surface, and, like the one 
that has just been discussed, presents many pitfalls. Without 
troubling ourselves with theories which are unsupported by 
statistical data let us consider some of the more important 
contributions to the solution of our problem. 
With the increasing age of parents there is apparently an 
increased percentage of abortions and stillbirths if we except the 
offspring of very young mothers. Data from Paris and Buda- 
Pest are given in the following table from Prof. Gini: 
Relations of Age of Parents to Percentage of Abortions and Stillbirths 
Paris, 1903-1909 Buda-Pest, 1903-1904 
Apap ine Legitimate Illegitimate Legitimate Illegitimate 
Miscar-| Still- | Miscar-| Still- | Miscar-| Still- | Miscar-| Still- 
riages | births| riages | births | riages | births| riages | births 
TS H20h coed acaees B63. | t.92'| $4 |. 2o4qe 6.25 |1.61] 6.39 | 3.11 
DOM 24 ee deern s Seacoicee 4.08 | 2.37] 6.21 | 2.88 8.05 | 1.90 | 11.03 | 3.73 
25=20 suceeielnaeee5 5-46 | 2.62] 7.05 | 3.68 | 11.42 | 2.61 | 10.98 | 4.37 
30-34 v4 eee eeess G2r§ |325% | 8x23 a 14.09 13.45] 9.62 | 4.95 
857802 tetas ess 7-39 14.33 | 6.83 | 4.14 
AOTAA sc ha seuienya nes 6.65 |6.07| 9-21 | 5 07) | 7.49 |5.39| 8.20 | 6.61 
A5. OF OVET Sines 45% 11.77 |6.67] 8.76 | 9.49 
Here it is shown that with the exception of some irregularities 
in the first horizontal column giving the percentage of miscar- 
riages and stillbirths of mothers below 20 years of age, there is 
a general increase in the percentage of both miscarriages and 
stillbirths as the age of the mother increases. Both kinds of 
American men of science (Sci., Mar. 5, 1917), and by the (as yet unpublished) 
researches of two of my students. 
