Quincy July 24. 1805
In the course of your industrious researches, in natural History have you ever given a particular attention to the generation of Shell fish? Will you be so good as to inform me in what Book this subject has been most fully treated? I suspect, but it is only a suspicion, that a great part of them are hatched by the sun, upon the Surface of the ocean; and that the proscess has been carried on, from the beginning of the World, on every Part of every Sea. How can We otherwise account for those immense quantities of shells, which we know exist? The Medusa which English and American Sailors, call, the Portugese Man of War, and is found sailing in every Sea, is a Shell fish in Embrio, the Spat or Egg as I conjecture is hatched by the Sun, on the surface of the Water. The Spatt or Eggs of Oysters float on the Waves and are deposited on the sands and flatts, all round the Island of Great Britain. At Cowes, on the Isle of Wight I saw boats from Colchester, daily employed in collecting this Spat, to carry home, to be deposited on the Oyster grounds at that place, where they grow very fast. Whether the Eggs laid by the Shell fish at the Bottom of the Sea, are light enough to rise to the Surface and are there blown about with the Waves by the Winds, until they are hatched by the Warmth of the Sun, I know not and can only conjecture. Mr Mappa of New York, observed in the Eastern Asiatick Seas, various Species of foam floating on the Waves, which he thought preparatory matter for testacious and crustacious fishes. On my Passage to America from England in 1788, the Lucretia was becalmed, for many hours in the Gulph Stream. Seeing a Multitude of Portugese Men of War in all directions about the ship when Captain Callahan Sent out his Boats to ascertain the Course and Velocity of the Current, I requested the Boatswains to take some pails and bring me a number of those Curiosities. They readily agreed, and made of it a gay amusement. When they took hold of them, by the <
[. . .]> Feelers, they would affect to roar out as if they had been shot. The Creature has a quality in him, which the Seaman calls a Caustic, a Corrosive and Sometimes a Poison. I know not whether it has been ascertained to be any thing of this kind, or whether it is Electricity. It is something which gives a shock, when it is touched. They brought me a Number, Say ten or a dozen. Each was a bundle of Gristle and Strings, Some of them as large as a Hat. Each of them had a shell fish growing in the inside in the Center of this Gristle. I saw a Cockle in one, a Muscle in another, a Scollop in a third, and one of the great Clams in a fourth. These observations Suggested to me, the Idea, which is however nothing more than conjecture, that the Eggs may be hatched by the Sun and float about in the shape of the Medusa, till the shell fish is compleatly formed, and by its weight drops out of its decaying gristly Vehicle, and sinks down to the Bottom, for the nourishment of Sharks Tortoises or other voracious fishes, whose Jaws and teeth are strong enough to grind, and stomachs capable of digesting shell and fish together. In a warm Morning in calm Weather, I have seen, a multitude of little red or yellow specks, no bigger than a thimble, floating in all directions round the Ship and been told by the Seamen that they were all young Portugese Men of War.
Reading the Manuscript Journals of Captain Joseph Ingrahams Voyage to the North West Coast of America, round Cape Horn in the Hope in 1790 in the tenth page of the first Volume, I find this account that "On the 12th. of December We observed many ridges in the sea, extending South West and North East, as far as the eye could reach, which discoloured the water very much, resembling blood. On dipping some of it up, it was found to be Fish Spawn. We passed through vast quantities of these on the passage, but as to their peculiar species, I am not Philosopher enough to determine." In the Second Volume of the Journal page 78, on the 20 of June 1791. lat 36.58 N. Long 83,35 West of Boston "The sea was full of what Seamen call Portugese Men of War—Clusters of Barnacles, Such as fasten to Ships Bottoms, but these were soft, without Shell. Besides these We picked up Several Shells resembling garden Snails, but of an elegant deep blue Colour. On putting these into a Small Vial of Spirits, the whole was immediately tinged but much paler than the Shell; these contained an Animal Substance, which would occasion any part it touched to smart exceedingly."
Nature, it should seem has provided these Creatures with that corrosive or electric quality, to prevent the larger fish from devouring them in their tender growing state.
I know not whether the causes which conspire to the formation of Shells or the manner of their operation, have been discovered. Rumors Hypothesis, is scarcely plausible, that this Substance is formed by the perspiration of the Animal hardening on its Surface: a transudation of earthy particles united only by juxtaposition Herissant alledges experiment for the discovery that they are organical, and composed of two Substances, one cretaceous and the other of an Animal nature. By an Analysis he Seperated these parts, and found in one of them a Soft Substance, consisting of innumerable membranes of a retiform appearance, which constitute the Animal part of the shell, and through a Microscope exhibit proofs of a vacular Structure. This membranous Substance, is a continuation of the tendinous fibres, by which the animal is fixed to the Shell, the hardness of which is owing to the Earthy Particles conveyed through the Vessells of the Animal, which encrust the Meshes, formed by these reticular filaments or membranous Substances.
The Shells which I saw, in the various Medusas which I examined exhibited an appearance conformable to this Theory. The Fibres and Membranes were distinguishable by the naked Eye, and appeared to be filling up and hardening with a viscous matter, circulating from some central part of the System, i.e of the animal. The Shells were in various Stages of their growth. In Some the Bivalves appeared to be nearly compleatd and almost closed. In others The Membranes and fibres of their shells were but beginning to assume their <
shapes> organical Shapes and were yet little more than a Jelly.
The whole object called the Medusa, resembles in some respects a Walnut or more properly a Cocoa Nut, in the Center is the Mint or Milk, surrounded by a very close and hard shell, over which is another shell or Coat of a more loose fibrous and coarse contexture. The Portugese Man of War has an animal at the Center, over whom a crustaceous Covering grows first and over that a more loose and gelatinous Covering with as many Strings growing round it and hanging down in the Water, as Medusa had of Snakes for her Hair. But the whole appears to be one System, all growing together from the same seed or Egg as the Center and spring of Life and increase.
I at first intended only to have stated the facts which I saw and have asked your explanation of them: But I have wandered into very uncertain Speculations which I hope you will pardon, to / your very good friend and humble servant.
MHi: Adams-Waterhouse Collection.