54 
AN EARLY HUMAN OVUM 
containing no blood-vessels. The curetting was performed 21 clays after 
the onset of the last menstruation, which lasted 5 days, leaving a clear 
period of 16 days, and this in all probability represents the maximum age 
of the ovum. Merttens regarded it as much younger than 16 days. 
It could hardly be less than 14| days when compared with the present 
ovum or more than 15^ days when its history is considered. 
IV.—Ovum of Beneke. 
The cavity of the ovum measures 4 , 2x2 , 2xl , 2 mm. and the 
embryo appears to be rather younger than that of ovum “v. Herff” of 
v. Spee. It was obtained by curetting on 30th March, 1903. The 
last menstruation extended from 5th to 10th March. There was no 
cohabitation after 22nd March. The period of 8 days between this and the 
operation is however unimportant, since by comparison with the present 
ovum the minimum age could scarcely be less than 15 days. The period 
of twenty days from the end of menstruation to the date of operation 
represents the maximum possible. Probably sixteen to seventeen days 
would be a fairly accurate estimate. 
V.—Ovum “ v. Herff” of Graf v. Spee. 
This specimen was obtained in a decidual cast expelled by abortion 
2 days after the onset of influenza, and, as we have ascertained 
from the author, exactly five weeks from the end of the last menstrual 
period. Allowing 5 days for the period, the abortion occurred 40 days 
after the date of last menstruation and 12 days from the expected 
menstruation. The implantation cavity measured 7 x 5'5 mm.—the external 
diameter of ovum 6 x 4'5 mm.—blastocyst 4 mm.—embryonic rudiment 
'37 mm. There were definite but very short villi. The state of preserva¬ 
tion is extremely good. The age of this ovum may be estimated as from 
17 to 18 days. 
VI.—Ovum No. 1 of Leopold. 
The blastocyst measures externally 6 x 6'5 mm., internally 4 x 37 mm. 
It was found in a uterus which had been excised on account of carcinoma 
