408 MALL. [Vor. XII. 
there is only an umbilical cord. The ovum was aborted fifty- 
four days after the first lapsed period, and was 30 mm. in 
diameter. The cord was 2 mm. in diameter and 9 mm. long. 
Its embryonic end seemed to be cut off abruptly, and was 
covered with a small mass of round cells. I give this example 
only to show that the embryo may be entirely wanting with a 
perfect cord and membranes. 
A large per cent of young ova which come into the embry- 
ologist’s hands are abnormal. According to Professor His’s 
TABLE OF ABNORMAL OVA. 

DIAMETER OF 


No. DIANE TEe OF AC Ue FROM WHOM OBTAINED. 
XIII 8 mm. 1.4 mm. Prof. His’s No. XLIV, Leipzig. 
XIV 30, << Babes Dr. Friedenwald, Baltimore, Md. 
KX LG ae 2, «6 Dr. Williams, Baltimore, Md. 
XXI 0} eG Dr. Cullen, London, Canada. 
XXXVII 2 bine 2st Dr. Gould, Philadelphia, Pa. 
LVIII oy GG Dr. Howard, Cleveland, Ohio. 
XXXII sfoy Z5cO) is Dr. Booker, Baltimore, Md. 
XXIV 20m — Dr. Miller, Baltimore, Md. 
XXIX Bom — Dr. Booker, Baltimore, Md. 
ION gon < — Dr. Watson, Baltimore, Md. 


It does not necessarily follow that these embryos are all less than six weeks 
old, for the menstrual history of the mother indicates that some of them must be 
considerably older. This is one source of error in obtaining the high per cent of 
abnormal ova among young embryos. The statistics will not be accurate until the 
menstrual history accompanies the measurements. 
experience over half of the ova less than three weeks old are 
abnormal, while of those of four and five weeks one quarter are 
abnormal. In my collection there are ten abnormal ova among 
twenty-six ova which are less than six weeks old. Of these 
ten specimens three contained no embryos at all, one (No. 
XXXVII) contained the cord only, and six were of the 
nodular form. Of this group of six, three contained a double 
vesicle with a kind of fibrous capsule, to a great extent similar 
to the mesoderm of the chorion. One of these is His’s Embryo 
XLIV, which is frequently described in the books as a normal 
