392 
MINOT. [Von i 
nal twigs are reached; the whole of the space between the 
chorion and decidua is occupied by these ramifications; the 
Cut rg.—Villous stem from a 
placenta of the fifth month. xX 9 
diams. 
branches and twigs, as the illus- 
tration shows, are extremely irregu- 
lar and variable, although in gen- 
eral they may be described as 
club-shaped, being more or less 
constricted at their bases. The 
branches may be bigger than the 
trunk which bears them, or of any 
less size; some of the smallest are 
merely slender outgrowths of the 
epithelial covering of the villus, 
such as have already been alluded 
to. Gradually there is a change. 
During the fifth month we find 
the irregularity, though still very 
marked, decidedly less exaggerated, 
Cut 14; the branches tend to go 
off at more nearly right angles; 
one finds very numerous free ends, 
as of course only a small proportion 
of the branches touch the decidual surface; the branches, too, 
are less out of proportion to the stems, less constricted at 
their bases, or, in other words, less remote from the cylin- 
drical form; the awkward cucumber shapes of the twelfth 
week are no longer found except here and there. The 
change continues in the same direction; that is, is towards 
Cut 15.— Terminal villi of a placenta at full term. The little spots represent the 
proliferation islands of the covering epithelium. 
