I0 o6 COMPARATIVE. HISTORICAL. 



He noted the glandular character of the prostate and named the seminal vesicles 

 and the epididymis. Aretasus (81 A. D.) recognized the decidua; Galen (131-203 

 A. D.) the oval foramen and the passage of the blood in the fetus through it and 

 through the ductus arteriosus. He was familiar with the physiological relations 

 between the vessels of the breasts and the uterus, and he knew that the uterus con- 

 tracted upon pressure. The Talmud contains the statement that an animal with an 

 extirpated uterus can live; that the pubic bones separate during labor, and an 

 account of a successful Cesarean section, with a living mother and child, performed 

 at the request of Cleopatra. Sylvius (1555) described the valve of the oval 

 foramen, Vesalius (1546) the follicles of the ovary, Eustachius (died 1570) the 

 ductus arteriosus (Botalli) and the branches of the umbilical vein to the liver. 

 Arantius examined the duct named after him, and stated that the umbilical 

 arteries do not anastomose with the maternal vessels in the placenta. Libavins 

 (1597) makes the statement that a child had cried aloud in the uterus. Riolan 

 (1618) recognized the corpus Highmori. Pavius (1657) examined the position 

 of the testicles in the inguinal region of the fetus. Harvey (1633) laid down the 

 fundamental principle: Omne vivum ex ovo. Fabricius ab Aquapendente (1600) 

 described the embryological development of birds. Regner de Graaf (1668) 

 described the ovarian follicle named after him; he found the ovum of mammals 

 in the oviduct. He produced erection in the cadaver through tense injection 

 of the cavernous body. Mayon (1679) observed in the placenta the respiratory 

 activity of the lung. Schwammerdam (died 1685) discovered metamorphosis; 

 he developed the butterfly from the caterpillar before the Grand Duke of Tuscany. 

 He described the cleavage of the frog's egg. Malpighi (died 1694) described the 

 embryology of the chick, with illustrations. The first half of the eighteenth 

 century was given up to a discussion as to whether the ovum or the semen 

 was the more important in development (ovists and animalculists) ; further, 

 whether the progeny was newly formed in the ovum (epigenesis) , or whether it 

 merely evolved and grew, thus lodged in the ovum as a being already formed 

 (evolution) . The ancients attributed the fructifying power to the odor of semen 

 (aura seminalis) . The question of spontaneous generation has been studied 

 exhaustively particularly since the time of Needham (1745), and it has, until 

 recent times, been made the subject of numerous investigations, until it was 

 finally overthrown chiefly through the efforts of Pasteur and of Robt. Koch 

 and his pupils. 



A new epoch began with Caspar Fried. Wolff (1759), who first taught the 

 formation of the embryo from germinal layers, and who, besides, first described 

 the tissues as composed of minute "globules" (cells) an idea that was first thor- 

 oughly investigated by Schleiden (1838) with respect to plants, and by Schwann 

 (1839) with respect to animals. Wolff published, as a model of investigation 

 in special embryology, a monograph upon the development of the gut. Will. 

 Hunter described (1775) the fetal membranes and the pregnant uterus, Sommering 

 (1799) the development of the external bodily form of man, Oken and Kieser 

 that of the intestine. The intermaxillary bone in man was viewed by Goethe 

 (1786) in its correct significance; he also suggested the correct morphological 

 conception of the development of cleft palate. Even prior to 1791 Goethe recog- 

 nized the construction of the cranium from vertebra. Tiedemann (1816) de- 

 scribed the development of the brain, Meckel that of monstrosities. The work 

 of Pander (1817), Carl Ernst v. Baer (1828-1834), Rathke, Th. Bischoff, Robert 

 Remak and many other living investigators, laid the foundation for studies of 

 the development of individual organs from the three germinal layers. Theodore 

 Schwann first (1839) traced the development of all of the tissues from the prim- 

 ordial germinal cells to the stage of complete evolution. 



