8 
Blenkins^ on an Early Human Ovum. 
of Wagner^ Miiller^ Coste^ BischofF^ and other distinguished 
observers; and the result of my own examinations entirely 
accords with the conclusions they have arrived at ; and I 
consider M. Velpeau in error in regarding the magma reticu- 
lare_, contained in the endochorion^ as the true analogue of 
the allantois of mammalian animals. 
I pass now to the examination of the embryo itself. As 
before mentioned_, I found it to be closely surrounded by the 
delicate amnion^ and slightly exceeding the one sixth of an 
inch in length. The head is very distinctly recognised^ with 
its three cerebral divisions or vesicles. The rudimentary 
eye is visible with some difficulty,, from the absence of 
pigment^ but when viewed with strong reflected light it 
may be discernedj and what is developed seems to consist of 
the posterior part of the sclerotic coat only. The eye of the 
opposite side may be seen when the specimen is turned^ so 
far corroborating the opinion of Bae. and Bischofi*^ that they 
are separate from their commencement ; for, according to 
these authorities, the malformed embryo designated cyclops is 
the result of an arrested develop: ent of the first cerebral cell, 
in consequence of which the rudiments of the two eyes approach 
and are confounded together. Owing to the position of the 
head, which is bent forwards, I am unable to see distinctly the 
branchial fissures ; I fancy two of them can be discovered, 
but owing to the specimen having been immersed in spirit, 
I am afraid that any attempt at separation now would only 
mutilate it. The heart is distinctly observed occupying the 
centre of the cleft, which is afterwards to be inclosed to form 
the thorax and abdomen ; on either side are two masses which 
must be the liver, of large size even at this early period. The 
foundation of the alimentary canal seems to be laid, for by 
transmitting a strong light through the specimen a curved 
body can be seen connected both with the allantois and 
umbilical vesicle. The Wolffian body or primordial kidney 
cannot be detected ; according to BischofF, the commencement 
of their evolution precedes the liver. I have no doubt they 
are present but hidden by the allantois, and I am unwilling 
to disturb this latter part, about which there has been so 
much discussion and controversy, and which is so remarkably 
well seen in this ovum. 
The cephalic extremities are very distinct under the form 
of fin-like processes, but the caudal members have not yet 
protruded ; a slight prominence or fulness may, however, be 
noticed just above the coccyx on either side, denoting the 
points where they are about to spring from. Velpeau asserts 
that the rudimental limbs appear simultaneously ; such cer- 
