184 STUDIES ON PATHOLOGIC OVA. 



taneous ones and therefore represent the inevitable mortality. Age classification 

 was based upon the sitting height (Keibel and Mall, 1910). Both normal and 

 pathological fetuses were used in this study. These were for the most part white. 

 In a limited number of cases no parental history was available; however, it is 

 certain that a great majority of these also were white. Among the specimens other 

 than white there is a preponderance of negroes, with a total of 201. The sex-ratios 

 of these fetuses in the various months of pregnancy are given in table K. The 

 pathological fetuses alone show a sex-ratio of 103.7, a proportion which indicates 

 that the two sexes become pathological with about the same relative frequency. 

 The sex-ratio of all the negro fetuses is 105.1, and of all the Filipinos 182.1. The 

 material on which these latter ratios are based is, however, too small to draw any 

 safe conclusion from them. 



The greatest deviations in the ratios obtained by Auerbach and by Carvallo, 

 on the one hand, and by the author on the other, occur in the third and .fourth 

 months, in which Auerbach found the ratios to be 322 and 229, and Carvallo 250. 

 The author's corresponding figures are very much lower, namely, 121 and 117, 

 respectively. The great excess of male abortions in the early months of pregnancy, 

 as found by Auerbach and Carvallo, may find its explanation in the fact that in 

 the statistics used by them the sex was determined by different individuals who 

 had not the specialized knowledge necessary for such determination on young 

 fetuses. The same source of error exists in case of statistics of abortions throughout 

 whole countries as used, for instance, by Nichols. 1 Early in the differentiation 

 of the external genitalia only the expert can state the sex with certainty. At this 

 time, and even later, the inexperienced, misled by the size of the clitoris as well as 

 by other factors, may erroneously determine the female fetus as male. Fewer 

 errors would be made on specimens from the latter part of the third and the fourth 

 months if only those definitely male were reported as such, and all the doubtful 

 ones were designated as female. Even granted that larger statistics might raise 

 the sex-ratio of abortions, the latter would never reach the high figures stated by 

 Auerbach, by Carvallo, and assumed by others. Just as the sex-ratio of mortality 

 following birth varies according to age, so it is found to be true during the pre- 

 natal period. The author's material showed a high sex-ratio in the third and 

 fourth months. In the fifth to the seventh month it became very much lower, to 

 rise again in the eighth to the tenth month, attaining a higher figure than in any 

 previous period. An analogous changing of the sex-ratio of intrauterine mortality 

 was found by Auerbach and by Nichols with only slight differences in the duration 

 of the periods of high and low ratios, but with considerable differences in the ratios 

 themselves. Nothing is known in regard to the sex-ratio of abortions during the 

 first two months of pregnancy; however, that of the third month might be used 

 hypothetically for this period. The author's material from the fifth to the seventh 

 month shows an average of 101.9, but owing to the variability in the individual 

 months it is quite probable that the number of male and that of female fetuses 



1 The writer had an opportunity to compare the death certificates of a large number of abortions and still-births with 

 his own findings on the specimens themselves, and found a surprisingly high percentage of errors in sex determination in 

 the certificates, sometimes even on full-term fetuses. 



