128 MALL. [VoL. XIX. 
less and less likely to be found. To be sure, the diseased 
specimen may be retained in the uterus for a long time as a 
mole, with or without an embryo, but if the chorion is not 
affected during the first few months of pregnancy it is likely 
to go on to full term, or if it is aborted so late it rarely con- 
tains a dwarfed embryo. Furthermore, infections of the 
uterus are infrequent after pregnancy is well under way, and 
in case it does take place, the probability of its attacking the 
whole chorion is slight. The embryo would probably with- 
stand the insult, since it is now more differentiated and more 
resistant. 
There are in my collection ten pathological specimens of 
the seventh week and half of them may be normal, at least 
the changes in them are but slight. Furthermore, after the 
seventh week there is but one pathological specimen a week 
until the fourteenth week, and none from this time until the 
end of pregnancy. 
A summary of the embryos brought together in the various 
tables is as follows: 
Vesicular forins 2 Ce oe tere oe eee 19 
Ova with neither embryo nor amnion ........ 2 
Ova with amnion but without embryo ........ 15 
Pathological embryos of the second week ...... 4 
Pathological embryos of the third week ...... 18 
Pathological embryos of the fourth week ...... 21 
Pathological embryos of the fifth week ....... 13 
Pathological embryos of the sixth week ....... 2 
Pathological embryos of the seventh week ..... 10 
Pathological embryos of the eighth week ...... 2 
Pathological embryos of the ninth week ...... I 
Pathological embryos of the tenth week ....... O 
Pathological embryos of the eleventh week..... I 
Pathological embryos of the twelfth week ..... O 
Pathological embryos of the thirteenth week .... 1 
Pathological embryos of the fourteenth week .. 1 
