HISTORICAL. 897 



through it, and through the ductus arteriosus. He was also aware of the physiological relation 

 between the breast and the blood-vessels of the uterus, and he described how the uterus con- 

 tracted on pressure being applied to it. In the Talmud it is stated that an animal with its 

 uterus extirpated may live, that the pubes separates during birth, and there is a record of a case 

 of Csesarian section, the child being saved. Sylvius described the value of the foramen ovale ; 

 Vesalius (1540) the ovarian follicles ; Eustachius (+ 1570) the ductus arteriosus (Botalli) and the 

 branches of the umbilical vein to the liver. Arantius investigated the duct which bears his 

 name, and he asserted that the umbilical arteries do not anastomose with the maternal vessels 

 in the placenta. In Libavius (1597) it is stated that the child may cry in utero. Riolan (1618) 

 was aware of the existence of the corpus Highmorianum testis. Pavius (1657) investigated the 

 position of the testes in the lumbar region of the fcetus. Harvey (1633) stated the funda- 

 mental axiom, "Omne vivitm ex ovo." Fabricius ab Aquapendente (1600) collected the materials 

 known for the history of the development of the chick. Regner de Graaf described more care- 

 fully the follicles which bear his name, and he found a mammalian ovum in the Fallopian tube 

 Swammerdam (f 1685) discovered metamorphosis, and he dissected a butterfly from the 

 chrysalis before the Grand Duke of Tuscany. He described the cleavage of the frog's egg. 

 Malpighi (+ 1694) gave a good description of the development of the chick with illustrations. 

 Hartsoecker (1730) asserted that the spermatozoa pass into the ovum. The first half of the 

 18th century was occupied with a discussion as to whether the ovum or the sperm was the more 

 important for the new formation (the Ovulists and Spermatists) ; and also as to whether the 

 fcetus was formed or developed within the ovum (Epigenesis), or if it merely increased in 

 growth. The question of spontaneous generation has been frequently investigated since the 

 time of Needham in 1745. 



New Epoch. A new epoch began with Caspar Fried. Wolff (1759), who was the first to 

 teach that the embryo was formed from layers, and that the tissues were composed of smaller 

 parts (corresponding to the cells of the present period). He observed exactly the formation of 

 the intestine. William Hunter (1775) described the membranes of the pregnant uterus. 

 Soemmering (1799) described the formation of the external human configuration, and Oken and 

 Kieser that of the intestines. Oken and Goethe taught that the skull was composed of 

 vertebra?. Tiedemann described the formation of the brain, and Meckel that of monsters. 

 The basis for the study of the development of an animal from the layers of the embryo was laid 

 by the researches of Pander (1817), Carl Ernst v. Baer (1828-1834), Remak, and many other 

 observers ; and Schwann was the first to trace the development of all the tissues from the ovum, 

 [Schleiden enunciated the cell-theory with reference to the minute structure of vegetable tissues, 

 while Schwann applied the theory to the structure of animal tissues. Amongst those whose 

 names are most prominent in connection with the evolution of this theory are Martin Barry, 

 von Mohl, Leydig, Remak, Goodsir, Virchow, Beale, Max Schultze, Briicke, and a host of recent 

 observers.] 



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