The ossified spot in the lower epiphysis of the humerus only appears some months after birth. The general appearance of a new-born infant is of value as indicating whether or not the fetus had reached maturity before its expulsion from the uterus. A healthy infant at term looks stout and well-nourished. The face is plump and is free from lanugo; miliaria are seen about the tip of the nose, but are not nearly so evident as they were in the ninth month of intra-uterine existence. The eyes are usually opened, the limbs move vigorously, and the child seizes with its lips the nipple when presented to it, and sucks with energy. The vernix caseosa is abundant only on the back of the child and on the flexor surface of the limbs. The nails project beyond the fingertips; the cartilage of the ears and nose feels firm; eyebrows and eyelashes are well developed; the hairs of the scalp are about an inch long; the bones of the head are hard and lie close together. The breasts in both sexes are large, and usually a thin fluid can be squeezed out of them. In boys the testicles are usually to be felt in the scrotum, although the tunica vaginalis is not yet closed. In girls the labia majora are usually approximated, although occasionally the nymphæ project between them. The Determination of Sex.-In all countries the number of male children born exceeds the number of females, the average proportion being 106 to 100; but, as more boys die than girls, by the time puberty is reached the sexes are about equal in number. The normal proportion is, however, in modern times much disturbed by the migratory tendencies affecting chiefly the male populations of old and long-settled countries. The law that governs the production of sex has long been a subject of discussion and speculation. The Hippocratic doctrine that the right ovary produced boys and the left girls was accepted for centuries, and upon this belief was founded the precept that women who desired male offspring should lie during coitus upon the right side, while those who desired daughters must lie upon the left side. By experiments upon animals, by the observation of women in whom one ovary was destroyed by disease or removed by an operation, and by a more complete knowledge of the mechanism of impregnation, the long-accepted teaching of Hippocrates was disproved, although not until comparatively recent times. At present it is yet undecided whether the question of sex is determined before impregnation occurs,that is, whether certain spermatic particles or ovules are predestined to produce males, while others produce females; whether the sex is impressed upon the ovule at the moment of conception, or whether the embryo is possessed of the elements of both sexes until one or the other acquires a preponderating influence owing to causes which may be operative during the early part of pregnancy. The first theory receives its chief support from the fact that unioval twins are invariably of the same sex, which looks as though the ovule was predestined in the ovary to the formation of one or the other sex. The last theory is based upon the study of plants and lower animals, in which the sex is only determined at some time after conception by the influence of nourishment; overfeeding being found to produce females, underfeeding to produce males. It is even possible in the case of certain animals to alter the sex, or at least to produce hermaphrodites, even after the sexual organs have begun to be differentiated. 1 This theory is further supported by the fact that in the human embryo the elements of both sexes are always present apparently in equal force during the early part of embryonal life. The belief that the sex of a human embryo is impressed upon it at the moment of conception rests upon the fact that in certain conditions of nutrition or sexual vigor in one or the other parent one sex preponderates, while under opposite conditions the other sex is most frequently produced. 2 Disregarding the time at which the sex is determined, the most diverse conditions have been called upon to explain apparent departures from the normal numerical relation of the sexes at birth. Illegitimacy, age of parents, 4 conception at certain periods after menstruation, 5 deformities in the female. pelvis, the nutrition or sexual vigor of the parents, the tendency of each sex to produce the opposite or the reverse, the 1 In the case of the larvæ of bees from impregnated eggs, when the female genital organs have begun to appear, if the nourishment is very insufficient, instead of becoming female workers these animals will actually develop into true hermaphrodites, with the organs of both sexes (Fürst). 2 Thury ("Zeitsch. f. w. Zoologie," 1863, Bd. xiii, S. 541) found in 29 experiments upon cattle that in every case, if connection occurred at the beginning of heat, females were produced; if at the end, males. 3 Fürst ("Archiv f. Gyn.," Bd. xxviii, S. 19) says that in illegitimate births the males fall below the average (based upon 807,332 cases). This coincides with my experience in the Maternity Hospital in more than 1000 cases of illegitimate births. 4 See Hofacker, "Ueber die Eigensch. welche sich von den Eltern auf die Nachk. vererben," 1828; Sadler, "Law of Population," London, 1830; Hecker, "Archiv f. Gyn.," Bd. vii, S. 448; Bidder, Zeitsch. f. Geburtsh.," Bd. ii, S. 358; Ahlfeld, "Archiv f. Gyn.," Bd. ix, S. 448; Wall, "The Causation of Sex," London "Lancet," 1887, i, pp. 261, 307. 5 Thury, loc. cit.; Coste, "Comptes Rendus," 1865; Schroeder, "Lehrbuch," 8te Aufl., 1884, S. 33; Fürst, "Kneben Ueberschuss nach Conception zur Zeit der postmenstruellen Anämie," Archiv f. Gyn.," Bd. xxviii, S. 18. Olshausen, "Klinische Beiträge," Halle, 1884; Linden, "Hat das enge Becken einen Einfluss auf die Entstehung des Geschlechts?" Dis. Inaug., Marburg, 1884; R. Dohrn, "Zeitsch. f. Geburtsh. u. Gyn.," Bd. xiv, S. 80. 7 See Fürst, loc. cit., and Schroeder, op. cit., S. 33. Also Schenk (Determination of Sex, authorized translation, Chicago, 1898), who believes that imperfect metabolism and glycosuria in the mother predispose to female offspring, while a strong nitrogenous diet and absence of sugar in the urine prepare a woman to bear male offspring. 8 See Fürst, loc. cit. tendency to produce that sex which is most needed to perpetuate the species,1 the season of the year,2 climate and altitude, and the degeneration of a race, as during the decadence of imperial Rome, 4—have all been advanced as reasons for apparent excess in the number of male or female births as the case might have been. All these theories, however, have been found either false or inadequate upon further investigation. An explanation that appeals to the author's reason is that the individual stronger in mental, physical, and sexual attributes will impress upon the ovule at the moment of impregnation that individual's sex. A perfectly satisfactory explanation of the determination of sex, however, is difficult to obtain, while the production of the sexes at will has hitherto been an impossibility. 5 Multiple Fetation.—It is the rule that but one fetus at a time is developed within the uterus of a human female. Once in about 120 pregnancies, however, two fetuses are developed simultaneously in the same uterus, so that twins are not of uncommon occurrence. Triplets are found once out of 7900, quadruplets once out of 371,126 births. Quintuplets are extremely rare. There is one case of sextuplets on record. Multiple fetation may be the result: (1) Of the impregnation of a single ovum that contains two or more germinal vesicles, or in which the formative material of the area germinativa divides; (2) of the impregnation of two or more ova which were contained either in one Graafian follicle or in separate follicles, the latter being situated either in one or both ovaries. There may be a hereditary disposition to multiple fetation. Boer reported, in 1808, an extraordinary example : A woman aged forty had in 11 pregnancies during twenty years given birth to 32 children, to wit: quadruplets twice, triplets six times, twins thrice. The woman herself was one of quadruplets and her mother had had 38 children. Her husband was one of twins, and there was a history of other plural births in his family. 1 Düsing, "Die Regulirung des Geschlechtsverhältnisses bei der Vermehrung der Menschen, Thiere, u. Pflanzen," Jena, 1884. 2 According to Düsing (loc. cit.), women impregnated in summer give birth to fewer boys than those impregnated in winter (conclusions based on more than 10,500,000 births). 3 Ploss found, in Saxony, that up to 2000 feet, the greater the altitude, the larger was the number of male births (at 2000 feet, 107.8 to 100). 4 Darwin's Collected Works. 5 According to statistics collected by Veit, based on more than 13,000,000 births, twins occur once in 89 pregnancies; in New York and Philadelphia the proportion is about I to 120. 6 Vassali, "Gaz. Med. Ital. Lombardia," Milano, 1888, No. 38. * Ahlfeld, "Archiv f. Gyn.,” Bd. ix, S. 196. 8" Wien. med. Wochens.," No. 3, 1897. If the multiple fetation is the result of the impregnation of a single ovum, there is but one chorion and one decidua reflexa, although each fetus is inclosed in its own amnion. 1 In these cases the sex of the fetuses is the same. The placentæ are usually found intimately united when expelled at term, presenting extensive arterial and venous anastomosesa condition that may give rise to the deformity of one of the Fig. 69.-Fetus papyraceus twins, known as acardia. But in the early stages of development each placenta, even in unioval twins, is separate. When the embryos are derived each from a separate ovum, there should be separate deciduæ reflexæ, chorions, and placenta. Occasionally, however, when the ova are implanted close together, the placenta may be joined, there may be but one decidua reflexa, and it may be difficult to detect the double layer of chorion that should separate the two ova. Although twins are not infrequently born, the condition should be regarded as pathological in its influence, at least, upon the fetus. From statistics collected by Schatz, it appears that in twins from different ova one is born dead in every twentythree cases, while from the same ovum the death-rate is one in six. One fetus will, perhaps, outstrip its fellow in growth, and divert the greater part of the nourishment from the mother to itself, thus growing rapidly and encroaching so upon the room that should belong to the weaker fetus that the 1 Occasionally two fetuses are found in a single amniotic cavity, which is to be explained (1) by the atrophy and absorption of the contiguous amniotic walls; (2) by rupture of the amnion in the latter months from the vigorous movements of the fetus; or (3) by the development of but a single amnion from the very beginning (Myschkin, Virchow's "Archiv," Bd. cviii, S. 133, 146). 2 Archiv f. Gyn.," Bd. xxix, S. 438. latter is killed and finally pressed flat against the uterine wall (fetus papyraceus). Hydramnios is also very common in twin pregnancies, and occasionally one fetus is converted into an acardiac monster. If the fetuses of a twin pregnancy escape the dangers of intra-uterine life, there are many complications awaiting them in labor. Should one fetus die during pregnancy, it is usually retained until term, when the living and dead children are cast off together, widely different in appearance and development; or else one ovum may be aborted at an early period of pregnancy, while the other goes on developing until term.2 Even though both children have been retained in utero an equal length of time, there is usually a marked difference in their length and weight, especially if they have resided in one ovum. In cases of uterus duplex, fetuses of different ages have been found in the two divisions of the uterus. Fordyce Barker reports a case of delivery of two mature children from a woman with a double uterus, one male, the other female, at an interval of two months. Upon such cases, and also upon the fact that of twins in negresses rarely one is light and the other dark, showing probably different paternity, has been based the theory of superfetation; but as there is no clear proof, as yet, of the occurrence of ovulation during pregnancy, the possibility of the impregnation of ovules which escaped from their Graafian follicles at rather wide intervals of time, say weeks or months, is doubtful. 5 CHAPTER IV. The Development, the Anomalies, and the Diseases of the Fetal Appendages: the Membranes, the Placenta, and the Umbilical Cord. THE study of the development, anomalies, and diseases of the fetal appendages is necessary to a clear understanding of fetal pathology. First will be considered the development and diseases of the fetal appendages springing directly from the 1 Schultze, "Volkm. Samml. klin. Vorträge," No. 34. 2 Sirois, "L'Union médicale du Canada,' July, 1887; and Warren, "Am. Jour. Obstetrics," 1887. Schatz, loc. cit. * See Lusk, op. cit.. p. 233, ed. 1886. * For some interesting observations which would seem to indicate the possibility, at least, of ovulation during pregnancy, see "Ovulation During Pregnancy," Christopher, "Am. Jour. Obstetrics," 1886, p. 457 |