310 
Dr Duckworth, The histology of the 
Fig. 5. Section 134. Obj. §. Oc. No. 2 (x 4). Camera lucida, Leitz. 
The blastocyst is now seen in intimate contact with the maternal 
tissues. Special attention is directed to the positions occupied by 
red blood corpuscles which in many instances are situated among 
the cellular elements, and are not confined to the capillary vessels. 
a. red blood-cells extravasated. 
h. red blood-cells between uterus and blastocyst. 
c. capillary vessel. 
cl. villus (this corresponds to the “ balken ” of some writers). 
e. embryonic mesoderm. 
f portion of a villus in contact with uterine tissues. 
g. cells apparently derived from uterine epithelium, and 
possibly proliferating. 
h. uterine gland with somewhat dilated lumen. 
i. fibrinous intercellular exudation. 
j. fibrin-mass, possibly in a capillary vessel. 
Fig. 6. Section 266. Obj. f. Oc. 2 (x 4), Camera lucida, Leitz. 
The entry of the blood into an intervillous space can be traced 
here. A large gland is seen filled with red blood-cells, and into 
its distal end projects a mass of embryonic tissue. 
a. embryonic villus (ectoderm). 
b. embryonic mesoderm. 
c. red blood-cells extravasated. 
d. red blood-cells in an intervillous space. 
e. red blood-cells entering an intervillous space. 
f. embryonic tissue invading a gland (cf. Figs. 9, 10, 11). 
g. haemorrhage in the lumen of the gland. 
h. a gland traceable towards the intervillous spaces. 
i. a dilated capillary vessel. 
j. red blood-cells in a capillary vessel. 
Fig. 7. Section 266. Obj. Zeiss D. Oc. 2 (x 4). Enlarged view of the 
capillary vessel shewn in the centre of Fig. 6 (?'). The capillary 
wall is interrupted by intruding cells from embryonic tissues. No 
proliferation is seen in the endothelial cells lining the capillary. 
Red blood-cells have escaped from the vessel and are seen among 
the cells of the adjacent tissues. 
