EARLY HISTORY

Generation of Animals. The first reputable book dealing with reproduction, Generation of Animals, was written by Aristotle. Aristotle's outlook, although not always accurate, was rational considering the breadth of facts available during his time. Aristotle proposed that the fetus was modeled from menstrual blood coagulated by seminal fluid - after all, menstrual bleeding ceased during pregnancy. Menstrual fluid contained all the potential body parts. Semen provided "form" to the menstrual "matter" and contributed the soul. Although Aristotle had no knowledge of the paired ovaries, he (in chauvinistic style) surmised that the right (dominant) side of the body was "hotter and nobler" than the left, and therefore produced male fetuses. Aristotle described the nutritive role of the placenta and reasoned that the uterus was always internal to "protect the young creature." Lengths of gestation were presumably governed by cosmic forces.

The (conspicuous) testes were of particular interest to Aristotle. Aristotle documented the role of the testes in male reproductive functions by observing effects of castration in peripuberal and mature animals and men (that castration was used as punishment for sexual offenses and adultery can be traced to 1500 BC). It was evident that castrates did not usually "generate" - nonetheless, Aristotle was perplexed that a steer (soon after castration) was able to mount a cow and effect impregnation. Eunuchs (prepuberal castrates) did not develop secondary sex characteristics typical of adults; nor, in men, did they become bald (a sex-influenced trait expressed by androgen).

Incidentally, the Greeks called the testes "didymi" (twins); the curious comma-shaped organ attached to the posterior surface of each testis was the epididymis. The word testis was derived from the Latin, to "testify." Evidently during primeval times men would put a hand over their genitals when taking an oath.

Anatomical observations. Many endocrine organs were undoubtedly discovered in antiquity. The abdominal counterparts of the testes were not described until shortly after the publication of Generation of Animals; Herophilus, an Alexandrine Greek physician, is acknowledged for this finding (he named the ovaries the "female didymi").

Herophilus is also given credit for discovery of the human pineal gland. Due to its geographic location within the center of the brain, it was assumed to be the "seat-of-the-soul" (according to Aristotle the final resting place of the soul was in the heart). The pineal gland received its name from Galen around the time of Christ; he considered the gland to resemble a pine cone. The notion that the pineal gland and soul were synonymous was propagated by Descartes (seventeenth century) in his Treatise of Man. Descartes intuitively linked the function of the pineal gland with the optic nerves and eyes. By the early part of the twentieth century the pineal gland had fallen from fame - most scientists deemed the gland nothing more than a vestigial relic. Only during the last several decades has the photosensory role of the pineal gland in the seasonal control of reproduction been validated.

Galen described the pituitary gland in a less than flattering light - it was regarded as the area of the brain through which metabolic waste was filtered to the nasal passages (pituita = phlegm). This false perception endured beyond the Dark Ages and into the Renaissance. Ironically, the pituitary organ would later be elevated to the status of "master gland."

The systematic study of reproductive anatomy did not resume in earnest until the sixteenth century when Gabriele Fallopius described the oviducts. Vague accounts of ovarian structures were provided by Vesalius, Fallopius, Coiter, and Fabricius. Testicular tubules, the mature follicle, and corpus luteum (CL) were characterized in detail by Regnier de Graaf during the seventeenth century; the preovulatory follicle (Figure 1-1) bears his name. Malpighi, who worked with cow ovaries, named (posthumous, 1697) the CL ("yellow body"). By the close of the nineteenth century it had been deduced that the CL originated from the ovulated follicle.

Evidently de Graaf had mistaken the follicle for an egg. A definitive description of the follicle-enclosed "ovulum" was contributed by Karl Ernst von Baer in 1827. Early investigators assumed that ova were derived from epithelial cells that covered the surface of the ovary - hence, the misnomer "germinal" epithelium (germ cells actually emanate from an extragonadal source).

During the last half of the seventeenth century Antonie van Leeuwenhoek used a simple lens to examine semen of several animal species; he described the appearance of live "animalcules" within these samples. A flurry of heated debates followed concerning whether sperm cells had anything to do with formation of the embryo. Traditional preformationists contended that the embryo was fully formed in germ cells - probably within the egg. Epigenists argued that fusion of sperm ("seed") with an egg was required to concoct an embryo. The controversy was put to rest by the middle part of the nineteenth century when spermatozoa were proven to be the fertilizing agent (the site was the oviduct). Indeed, the technology to collect, split, and transfer embryos was on the horizon.

Meanwhile, early versions of the microscope were used to study embryonic development and to delineate the cellular components of the gonads. Histological studies by Kaspar Wolff (an active proponent of epigenesis) and Johannes Müller indicated that the reproductive tracts formed differentially from a primitive urogenital system common to both sexes. The embryonic origin of the anterior pituitary gland was traced from the roof-of-the-mouth by Martin Rathke.

Human fertility control. Contraception (temporary aversion of pregnancy), sterilization (permanent prevention of pregnancy), and induced abortion (artificial termination of pregnancy) have been practiced for thousands of years.

Much of the archaic literature dealing with contraception is of oriental descent. Systemic approaches of fertility control included ingesting quicksilver (mercury) fried in oil, live tadpoles, or mule uteri. Vaginal pessaries were composed of honey (which inhibited sperm motility) and crocodile dung. Rock salt, alum, and quinacrine were unknowingly used as spermicides. Sea sponges, inserted into the vagina to soak up semen, were used for centuries. Later, cervical caps and diaphragms were molded from wax, oil silk paper, and linen cloth.

Use of the intrauterine device (IUD) has also been linked to early Asian times. Rocks were apparently placed in the uteri of camels to prevent pregnancy. As far as we know, the first IUDs for human contraception were designed during the early 1900s - rings of silkworm gut wrapped with silver wire.

The origin of the condom (from the Latin condus, meaning receptacle) dates to the ancient Romans - they fashioned bladders of animals into repositories. Fallopius devised an archetype condom from a linen sheath; he advised its use to protect against "pleasure and danger" - the scavenging effects of venereal (after Venus, the goddess of love) diseases, mainly syphilis (hero of the 1530 French poem, Syphilus sive Morbus Gallicus), were well known.

Two natural time-honored methods of contraception are coitus interruptus (withdrawal of the penis before ejaculation) and breast-feeding. Withdrawal was denounced by some religious factions. As extreme as it may seem, it is stated in the Book of Genesis that Onan was put to death for "spilling semen on the ground." Women have suckled their babies for years to avoid pregnancy (menstrual cyclicity is repressed during lactation). Not surprisingly, these approaches have high failure rates (after six months with nursing).

The first tubal sterilization was performed in 1823. Until recently, tubal ligations were used mainly to prevent pregnancy in women who would require repeated cesarean sections. Vasectomies were first carried out in Sweden and England in 1894.

In early times physical trauma to the abdomen was the usual method of abortion. Greek women, as advocated by Hippocrates, used vehement exercise to achieve abortion. Direct invasive procedures, such as cervical dilation and curettage (scraping of the uterine wall) (D & C) and uterine infusions of irritants, were put into practice during the nineteenth century. The Comstock Law of 1873 was part of a campaign to legislate public morality in the United States - making the distribution of literature on sexuality, contraception, and abortion illegal; soon thereafter, elective abortions were banned in most states.

Finally, plants have been used for birth control and as abortifacients for centuries. One of the oldest known efficacious plants was called silphium; it was apparently used to extinction by the third or fourth century AD. Hippocrates mentioned the use of Queen Anne's Lace (Wild Carrot), an inhibitor of progesterone production and fetal growth - the seeds of which are evidently still in use today (eg., in parts of the rural United States). Other plants/fruits of alleged use are pennyroyal (which is toxic), asafoetida, artemisia, myrrh, rue, willow, date palm, pomegranate, cabbage, juniper, pine, onions, and acacia gum. The main problem with natural plant-based contraceptives is inconsistency of action.