90 QUARTERLY CHRONICLE. 
do not occur as normal structures in the contents of the 
testicular canals. (Henle, ‘Handb. d. System Anat.,’ ii Bd., 
s. 356, makes the same objection against Kolliker relative to 
the rolled-up sperm-threads.) 
3. In the testicular canals occur two sorts of cells (Henle), 
not only in mammalia, but also in birds and amphibia. Only 
the one kind, with smaller clear nuclei, enter upon the change 
into spermatozoa. Many peculiarities in the form of the 
sperm-elements are, without doubt, dependent on their some- 
times quick, sometimes slow, sometimes complete, and some- 
times imperfect development. 
4. The relations of the parts in their formation appear 
in the simplest way in the frog. In semen taken from 
the testis long-shaped cells may be observed, in one 
end of which the rod-like nucleus has located itself, 
while the other grows out to a hair-like cilium. The 
peculiar cell-substance disappears more and more in 
further development, until there is only a small compact 
piece between cilium and nucleus left remaining. It is this 
which is the middle-piece in the complete spermatozooid, and 
we can therefore draw the parallel—the head, the nucleus; 
the middle-piece, the modified cell-substance; and the tail, 
the hair-like cilium formed from the material for a cell. 
(Ankermann also regards the spermatozooids of the frog 
each as consisting in itself of a nucleated cell, but he assigns 
to them a somewhat different mode of development. ) 
5. The main features are the same in the mammalia as in 
the frog, only that here the “ middle-piece” undergoes a 
more peculiar modification. The nucleus of the sperm-cell 
is intimately connected with the head of the spermatozooid. 
In quadrupeds the head is characteristic in its form, as in 
the mouse one can see lying at the edge of the yet round 
sperm-cell the nucleus already transformed, whilst from the 
side, more or less directly opposite, the tail sprouts forth. 
Thusalso the threesegments iu the spermatozoa of the mammal 
find their explanation in the manner of their development. 
Herr Schweigger-Seidel’s paper is illustrated by a plate 
containing drawings of the spermatozoa of the frog, triton, 
house hen, finch, sheep, field mouse, house mouse, hedge- 
hog, pig, guinea pig, and rabbit, in various stages of develop- 
ment. 
2. “ On the Alveolar Gelatinous Tumours,” by Professor 
Franz Eilhard Schulze.—This is apparently a valuable paper 
on the histology of the disease called Carcinoma alveolare by 
J. Miller, Cancer aréolaire gelatiniforme by Cruveilhier, 
Gelatiniform cancer by Carswell,and Gelatinoma,Gum cancer, 
&c., by others. It is illustrated by a clear and well-drawn plate. 
