THE MAMMALIAN EGG 



contents of the follicle passed, through the tubes in a fluid or un- 

 organized state, becoming later constituted into the uterine eggs. 

 His search of the Fallopian tubes did, in fact, reveal to him the 

 much smaller tubal eggs, but the observation was not generally 



Fig. 1 



'Eggs to be found in all sorts of females.' 

 A drawing published by Kerckring (1672). 



Fig. I depicts the ovaries, uterus and adnexae in the human subject. 



Figs. II and III, human ovarian 'eggs'. 



Fig. IV, cow ovarian 'eggs'. 



Figs. V and VI, human uterine 'eggs', opened to show contents. 



credited — the difference in size was incomprehensible and no one 

 could confirm the finding until Cruickshank did so over a hundred 

 years later. Cruickshank (1797) identified tubal rabbit eggs as early 

 as the third day after coitus but could not trace them back further 

 than this. Other investigators were no more successful and it was 

 not until thirty years later that the ovarian egg was finally recog- 

 nized. Von Baer (1827) announced the discovery with a well- 

 justified air of triumph — 'Led by curiosity ... I opened one of the 

 follicles and took up the minute object on the point of my knife, 

 finding that I could see it very distinctly and that it was surrounded 

 by mucus. When I placed it under the microscope I was utterly 

 astonished, for I saw an ovule just as I had already seen them in 

 the tubes, and so clearly that a blind man could hardly deny it' 

 (translation published by Corner, 1933). 



