THE HORMONES IN HUMAN REPRODUCTION 



embryo? Nothing has turned up, since the first edition of this 

 book was published, to cast any doubt upon the conclusion 

 that the hormonal action of the corpus luteum is necessary 

 for the survival of the early embryo in the uterus before its' 

 attachment, and for its implantation in the endometrium. A 

 number of considerations make it necessary, however, to 

 restate the matter somewhat differently. In a recent striking 

 investigation M. N. Runner of the Jackson Memorial Labora- 

 tory at Bar Harbor (Anatomical Record, 98, 1947, p. 1) 

 removed fertilized eggs of the guinea pig from the oviducts 

 and placed them in the anterior chamber of the eye, where 

 they could be observed with a microscope through the clear 

 cornea. It has been known for some time that the fertilized 

 mammalian egg can go on segmenting and reach the blasto- 

 cyst stage outside the mother, in tissue-culture dishes. The 

 motion pictures of W. H. Lewis (see page 56 and Plate XI) 

 were made from eggs cultured in that way. The anterior 

 chamber of the eye is well-known to be a favorable place for 

 the growth of transplanted tissues, for the aqueous humor 

 is an excellent physiological salt solution, and a good blood- 

 supply is readily available for tissues that become attached to 

 the iris (cf. Markee's grafts of endometrium, page 150). 

 Runner found that when placed in the eye, the fertilized eggs 

 of the guinea pig would continue dividing, would proceed to 

 the blastocyst stage and become implanted, or at least begin 

 to implant upon the iris. All these phenomena of embryonic 

 growth were found, moreover, to occur even though the 

 ovaries were removed or the eggs placed in the eye-chamber 

 of another animal which had not ovulated and therefore had 

 no corpora lutea. Indeed, the eyes of male mice proved to be 

 as favorable for growth of embryos as those of females. 



Some years ago J. S. Nicholas of Yale University operated 

 upon rats in such a way that the fertilized eggs passed out of 

 the oviduct into the abdominal cavity. Among a large number 

 of animals thus prepared there were a few cases in which the 



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