42 THE EMBEDDING OF THE OVUM. 



inent mucosa area, in a cavity of the interglandular connective 

 tissue of the mucosa, an ovum 1.5 x 2.5 mm. was situated. It 

 had but few villi and contained an embryo in a very rudimentary 

 stage. Between the surfaces of the chorion and uterine tissue, 

 here and there, small quantities of blood could be seen which es- 

 caped from ruptured vessels. The walls of the ovular chamber 

 were entirely made up of elements of the interglandular connec- 

 tive tissue. All the glands opened into the uterine cavity, none 

 into the ovum chamber. Like the ovum of Peters, the serotina, 

 i. e., the mucosa, between the ovum and uterine muscularis, con- 

 tained, within greatly dilated endothelial tubes, large blood clots 

 apparently formed still during life. This blood served a double 

 purpose, furnishing nutriment to the ovum and protecting the 

 deeper portions of the mucosa against the corrosive action of the 

 ovum. That portion of the envelope of the ovum which separ- 

 ates the cavum of the uterus from that of the ovum, consisted of 

 a thicker or thinner layer of interglandular connective tissue cov- 

 ered towards the uterine lumen by a single stratum of epi- 

 thelium." 



Thus it can be seen that also in this specimen the ovular en- 

 velope is formed by decidual tissue, none of the uterine glands 

 open into it, and near the ovum, especially in the serotina, large 

 blood masses lie in immensely dilated endothelial tubes. 



II. 



THE EMBEDDING OF THE OVUM. THE CAPSULARIS. 

 THE FIBRIN COVER ("GEWEBSPILZ OF PETERS"). 



Since it has been established by Graf von Spec for the guinea 

 pig and by Peters for the human being, that the ovule bores its 

 way through the surface of the mucosa, it has become the duty 

 of the later investigators to determine whether this is the only 

 mode of nidation or whether not occasionally a circumvallation 

 occurs arising from the mucosa surrounding the ovum. 



Pfannenstiel 1. c. page 194, is correct in saying: "The ovum de- 

 scribed by Peters is already completely or almost completely en- 

 veloped by the mucous membrane. In spite of the great value of 

 this specimen, in spite of the fact that it has revolutionized our 

 views concerning ovular nidation, we should not forget that this 

 is the only specimen extant of this early stage of development and 

 it would seem advisable not to go too far in its interpretation." 



