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PHYSIOLOGY 



CHAP. 



undergone by the uterine mucosa, by means of which the so-called 

 catamenial decidua is formed. We also described the haemorrhagic 



FIG. 79. The earliest stage known of the process of fixation of the human ovum. (Peter.) 

 1, ovum ; 2, outline of embryo : uterine epithelium wanting at point perforated by ovurn ; 

 4, openings of glands ; 5, connective tissue stroma of the mucosa ; 6, proliferated ectoderm 

 of ovum (trophoblast) with initial formation of villosities and extension of syncytium, 

 immerged in a network of sanguineous lacunae, continuous with the capillaries surrounding 

 the ovum ; 7, projection of the mesoderm ; 9, sections of glands ; 10, muscularis ; 11, 

 network of blood and fibrin, covering the opening made by ovum. 



and degenerative process which takes place in the mucosa when 

 the ovum arrives in the uterine cavity without being fertilised. 

 We must now see what occurs in the uterine mucosa when the 



