After this digression concerning varieties in the structure of the
heart, the author resumes his anatomy of the Squulns maximns, and
notices, among the peculiarities of the urinary passages, that there
is no proper urinary bladder, but a cavity comparatively small, that
is common to the urine and semen; since both the vasa. differentia
and ureters open into it at the distance of about four inches from
each other.
The holders in the male Squalus have been noticed before; but it is now added, that in each holder is a canal, communicating with a cavity between the skin and muscles of the abdomen, Which is stated to be eleven feet long and two Wide. The surfaces of this cavity are white, and extremely smooth; and it contains a mucus more vism'd than any known animal secretion.
Respecting the brain, it is remarked, that in the Squalus, as well as in fish in general, the cerebrum is wanting, unless the part from which the olfactory nerves arise be so called.
The eye is very small for the size of the fish; its largest diameter being not more than three inches, and its shortest only one inch and three quarters.
The straight muscles that surround the eye are so much stronger than would appear to the author requisite for moving so small a sphere, that he thinks such strength can only be required in adjust- ment of the eye for overcoming the stiffness of the sclerotic coat.
In a second letter which the author received from France, he is informed that the detonating oil was there originally procured by passing a mixture of chlorine and azote through aqueous solutions of sulphate or muriate of ammonia; but from the method of obtaining it in this country, it is evident that the azote is unnecessary, as it is obtained by exposure of any ammoniacal salt in solution to mere chlorine. The oily fluid obtained by these means has the specific gravity of 1'653. It is not congealed by cold, as the author had formerly supposed, but remains fluid even when cooled by a mixture of ice and muriate of lime.
When kept in water, it gradually disappears, and the water becomes acid, having the taste and smell of weak nitro-muriatic acid.
Concentrated muriatic acid decomposes it, disengaging chlorine, and forming muriate of ammonia.
In concentrated nitric acid it gives out azote.
In dilute sulphuric acid it yields a mixture of azote and oxygen.
In a strong solution of ammonia it detonates ; with a weak solution it yields azote.
With the muriates of sulphur and of phosphorus, or with sulphuret of carbon, it combines without any violence.
