THE DEVELOPMENT OF THE MOLE. 423 



lution, it then becomes possible to separate the two without 

 damage. 



Figs. 8 and 9 represent very faithfully the appearance of 

 ova of this age obtained by the above method. 



The wall of the vesicle is bulged out here and there into 

 papilla? where it projected into the mouths of the glands. The 

 elongated condition is due to the fact that when the uterus 

 Avas slit open the vesicle fell into that shape in which it 

 received the greatest amount of support from the surrounding 

 tissue. 



Tf it is not desired to examine the vesicle in a fresh state it 

 will be found advantageous to harden the embryo within the 

 uterus, and to dissect it out afterwards which is an easy 

 matter. 



In order to show the position and condition of the uterine 

 glands, I have drawn in fig. 51 a transverse section through 

 that region of the uterus from which the ovum represented in 

 fig. 8 was obtained. 



It will be seen that only on the free non-mesometric side of 

 the uterus are there any widely open mouths of glands ; while 

 upon reference to figs. 8 and 9, only that side of the ovum 

 around the embryonic area is seen to be prolonged into papillse- 

 form projections, and as the embryonic area lies against the 

 non-mesometric side of the uterus in the mole we may con- 

 clude the projections lie in the mouths of the glands. A 

 portion of the epithelium of the uterus abstracted fiom the 

 latter is drawn in fig. 52 ; it is seen to be prolonged into 

 hollow finger-like processes which line the uterine glands. 



Transverse sections of the embryonic area of this embryo 

 (fig. 28) show that it is formed throughout of two layers of 

 cells, epiblast and hypoblast. 



One of the prolongations of the vesicle wall has been cut at 

 one side of the embryonic area (pi) and another is shown in 

 fig. 29. They are seen to be formed wholly of epiblast, the 

 hypoblast not being extended into them. 



Of the hypoblast layer in the area I have nothing to add to 

 the account already given ; the epiblast, however, has under- 



