Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.Various
History
Philosophical transactions, Vol. L. Part I. For the year 1757.: Giving some account of the present undertakings, studies, and labours, of the ingenious, in many considerable parts of the world.
Various
Science -- Periodicals
Mons. Donati took last summer, according to his custom, a journey,
in order to prosecute his researches into natural history. He was
accompanied by Dr. Ascanius, Fellow of the Royal Society; who was still
in doubt about coral’s being a composition of animals. Mons. Donati
carried him to the sea of Provence. He ordered coral to be fished up
in his presence. He placed it in a large vessel full of water; and
carried this vessel on shore; where he soon convinced Dr. Ascanius, by
his own eyes, that coral is a mass of animals of the polype-kind.
Mons. Donati has written to me, that he has thoroughly satisfied
himself by his last observations, that the polypes are fixed to their
cells; of which he had before doubted. What he says afterwards of
coral appears to me to express with more truth and precision what we
ought to think of this kind of animals, than any of the descriptions,
which have been given since the new discoveries have changed our
sentiments on that subject. Polype-beds, and the cells, which they
contain, are commonly spoken of as being the work of polypes. They
are compared to the honeycomb made by bees. It is more exact to say,
that coral, and other coralline bodies, have the same relation to the
polypes united to them, that there is between the shell of a snail and
the snail itself, or between the bones of an animal, and the animal
itself. Mons. Donati’s words are as follow. “I am now of opinion,
that coral is nothing else than a real animal, which has a very great
number of heads. I consider the polypes of coral only as the heads of
the animal. This animal has a bone ramified in the shape of a shrub.
This bone is covered with a kind of flesh, which is the flesh of the
animal. My observations have discovered to me several analogies between
the animals of kinds approaching to this. There are, for instance,
keratophyta, which do not differ from coral, except in the bone or
part, that forms the prop of the animal. In the coral it is testaceous,
and in the keratophyta it is horny.”
The observations, which I have made upon some kind of polype-beds,
lead me to think, that what are called polypes, in those bodies,
which are observed to come out of and return into the cells, are more
than the heads of the animal. I have seen some, which had a bag,
into which pass’d their food, which I saw them swallow; and another
bag, into which passed the grossest part of that food, after it was
digested. This is the case, for instance, of the plumed polypes, which
I described at the end of the third memoir, in the work published by me
on one kind of fresh-water polypes.
Mons. Donati has observed divers very curious facts in the journey,
which he made into the mountains. He has, in particular, traced out an
immense bed of marine bodies. This bed crosses the highest mountains,
which separate Provence from Piedmont, and loses itself in the plains
of Piedmont.
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