THE EGG 



it is received into the open end of one of the two oviducts y 

 tubular conduits, each (in the human species) about 11.5 

 centimeters (43^ inches) long (Plates V and X). Medical 

 men and the general public usually call them "Fallopian 

 tubes," although Gabriele Fallopio (1523-1562) was not the 

 first to mention them and had no idea of their real function ; 

 he thought they were ventilators to let noxious vapors out 

 of the uterus. The walls of the oviducts are made, like the 

 intestines, of involuntary muscle cells. Their lining is a velvety 

 membrane which follows their channel all the way to the 

 uterus and joins the lining of that organ. The cells on the 

 surface of this membrane are beset with fine hairlike processes 

 ("cilia") lashing continuously downward, and thus producing 

 a current through the oviducts toward the uterus. These cilia 

 may be seen in Plate X, E. At their free ends, near the ovaries, 

 the oviducts open directly into the abdominal cavity by 

 handsome trumpet-shaped expansions with fringed edges cov- 

 ered by the velvety red lining tissue. One of the fringes of each 

 oviduct runs right on to the ovary. 



When we say the oviduct opens into the abdominal cavity, 

 we must not forget that the "cavity" is actually packed full 

 of intestines. When an egg escapes from the ovary, it does not 

 pop into a large vacant space ; it merely glides in a thin film 



Plate X. ^ (at top), oviduct (Fallopian tube) of Rhesus monkey, drawn 

 by J. F. Didusch from preparation by author. Enlarged 4 times. B, photograph 

 of living eggs of a mouse, in passage through the oviduct. The eggs are seen 

 through the walls of the oviduct, which is exceedingly thin in this small 

 mammal. Magnified about 45 times. Courtesy of H. O. Burdick. C, model of a 

 part of the oviduct of a rat, showing eggs in passage. Magnified about 33 times. 

 From an article by G. C. Huber, by courtesy of the Wistar Institute of 

 Anatomy and Biology. D, diagram showing comparative size of the egg of the 

 rabbit and the folds of the lining of the oviduct. Courtesy of G. H. Parker. E, 

 comparative size of the human egg and the cilia of the lining cells of the 

 oviduct. The cilia are seen as little brushlike clumps on the free ends of some 

 of the tall cells. Enlarged 600 times. This drawing was made by combining part 

 of a human egg described by Warren H. Lewis (see Plate VII, D) with a 

 picture of the epithelium of the oviduct from a paper by F. F. Snyder in the 

 Bulletin of Johns Hopkins Hospital. 



{ 45 } 



