224 
MR. NEWPORT ON THE IMPREGNATION OF 
suspension rather than in chemical combination. When placed on a single filter, the 
solution passed through with extreme difficulty and slowness. When a microscopic 
drop of the fluid so passed was examined with a power of three hundred diameters, 
it was found to contain a large quantity of granules suspended in clear fluid. When 
made to pass, but with still greater difficulty, through a second filter, it still contained 
a quantity of minute granules, but each less than one- half the diameter of the sperma- 
tozoon. It \?> possible, therefore, that some extremely minute granules may penetrate 
into the texture of the envelope, formed as it is of aggregations of cells ; but it seems 
to be very improbable that any of the larger-sized objects, such as the spermatozoa, 
can enter : and it is even much more improbable, that if the chief colour of the ova in 
my experiments was due, as I believe, to granules of carmine on the surface, and not 
in the interior of the ova, that in MM. Prevost and Dumas’ experiments with frog’s 
blood, the ova should have become reddened by the admission of particles of this 
into their interior, since it need scarcely be mentioned that the colour of the blood is 
due only to the particles suspended in it ; and MM. Prevost and Dumas remark, 
that they were not able to detect any blood-globules on the surface. To what else, 
then, than to these, or to their broken-down particles, could the reddened colour 
of the ova in their experiments be due ? 
The conclusion, then, to which I am led by these experiments is, that although the 
envelopes of the egg imbibe coloured fluid, they do so less easily than when the fluid 
is not coloured, unless it is in chemical combination ; and although atoms of solid 
matter, very much smaller than the spermatozoa, may possibly be carried by infiltra- 
tion into the texture of the egg-envelope by the act of endosmose during its expansion, 
it appears to be extremely unlikely that the large bodies of the spermatozoa are so 
carried in ; an improbability which is raised almost to a certainty by the fact that the 
spermatozoa are not seen attaehed to the egg with a centripetal direction of the axis 
of their bodies, but are constantly applied laterally to, or are entangled amongst the 
loose tissue of the surface, extended at length or partially folded on themselves. 
6. AGENCY OF SPERMATOZOA AS AFFECTED BY CHEMICAL MEDIA. 
The experiments with carmine having led to an unexpected result in the impedi- 
ment whieh this medium offers to the impregnation of the ovum when immersed in it 
before contact with the spermatozoa, I was desirous of ascertaining what effect would 
be produced on the ovum by the destruction of the spermatozoa by chemical means, 
immediately after they had been applied to it. Mr. Gulliver* long ago showed that 
the spermatozoa of different animals are variously affected by different chemical tests ; 
and Dr. Frerichs'|~, more recently, has found that a solution of caustic potass has 
the property of entirely dissolving and destroying them. This material, therefore, 
seemed to be peculiarly fitted for the object in view. But before any experiment, in 
* Proceedings of the Zoological Society, part 10. p. 101. July 26, 1842. 
t In Cyclopaedia of Anatomy and Physiology, Article “ Semen,” p. 506, January 1849. 
