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Description of an Early Human Embryo of about the fourth 
week of tJtero- gestation. By Arthur Farre^ M.D._, 
F.R.S._, Professor of Obstetric Medicine in King's College, 
London. 
(Read May 13tli, 1857.) 
In the year 1850 I had the honour of reading to this 
Society an account of a very early human embryo, the 
description and figures of which will be found in vol. iii, 
part ii, of the ^ Microscopical Transactions.^ 
Having in that paper briefly explained the circumstances 
which render it a matter of great difficulty to obtain perfect 
specimens of the human embryo at very early periods of 
development, such as the violent pressure which the ovum 
suffers in the act of expulsion from the uterus, and the rough 
handling which it usually undergoes before it reaches our 
hands, independent of the rarity of procuring aborted speci- 
mens which are quite normal in their development, I need 
not here again advert to this subject. But I may observe, 
that while the development of the mammalian ovum has been 
traced through all its stages in many species (by the inde- 
fatigable Bischoff for example), the embryo of man has not 
been so carefully examined, especially in its early stages, as 
might fairly be expected from the great interest of the sub- 
ject, even allowing for the impediments to the pursuit of 
human embryology to which I have just adverted. 
It appears to me that the best way of supplying this defi- 
ciency is for each individual, who may have the opportunity, 
to record his observations, though they may be only of 
isolated examples ; so that in time a number of such instances 
may be collated, and so a series may be obtained, which it is 
obvious, from the very nature of the subject, could not be 
formed in any other way. 
I make no apology, therefore, for again drawing the atten- 
tion of the members to this very interesting department of 
human phj^siology, by offering a brief description of another 
early human embryo which I have recently had the opportu- 
nity of examining. 
This specimen was passed by abortion, for which no very 
obvious cause could be assigned, the mother being at the 
time in perfect health. From circumstances antecedent to 
the occurrence, I am not able to fix the age of the embryo 
