316

Chili

1835 March 7-9

Infusoria (a) The sea some few leagues North of Concepcion was of a muddy color in great bands, certainly more than 1 or 2 miles long.— Again 60 miles South of Valparaiso the same appearance was very extensive; although 40 or 50 miles from the shore I though it was owing to a current of muddy water brought down from the Maypo. B Mr Sulivan however having drawn some up in a glass, thought he saw by the aid of a lens moving points.— I examined the water; — it was slightly stained as if by red dust.— & after leaving it for some time quiet, a cloud collected at the bottom: with a lens of one fourth of an inch focal distance, small hyaline spots might be seen darting about with great rapidity & frequently exploding. Examined with a much higher power [illeg], their shape is oval & contracted by a ring on around the centre from which line on all sides proceed curved little bristles setæ proceed & these are the organs of motion.— [sketch] One end of the body is narrower & more pointed than the other. It is very difficult to examine these animalculæ, for almost the instant motion ceases their bodies burst. Sometimes both ends burst at once, sometimes only one, & a quantity of coarse brownish granular matter is ejected which coheres very slightly.—

The ring with the setæ sometimes retains life sometimes its irritability, for a little while after the ends have ejected their contents, it continues a riggling uneven motion. The animal, an instant before bursting expands to half again its natural size; about 15 fifteen seconds after the rapid progressive motion has ceased, the explosion takes place.— In a few cases it was preceeded for a short interval by a rotatory motion on the longer axis. Directly perhaps 2 minutes Very soon, perhaps about two minutes after any number were isolated in

[316v]

(a) The granular matter is contained in a thin capsular membrane, to this membrane on the ring the transparent tapering fillets or bristles are fixed.— The motion of these setæ is that of collapsing on the obtuse end.—

The water only appeared as if it contained a little of the finest red dust.—

317

Chili

1835 March

Infusoria a drop of water, they thus perished.— The animal moves by the aid of the vibratory ciliæ with the narrow apex forwards, & generally with by rapid starts; The setæ are rapidly vibrating around the Body.— The immediate bursting of the body prevented any close examination; they would sometimes explode even whilst crossing the field of vision.— They are exceedingly minute and quite invisible to the naked eye, only being a trifle larger (before explosion) covering a space equal to the square of .001 of an inch. Their numbers are infinite, the smallest drop of water, which I could remove, containing very many.— We passed through in one day two masses of water thus stained, to day of which the latter of the two must have been several miles in extent. B the edge of the blue water & red water was quite perfectly defined.— What infinite numbers of these microscopical animals! — The weather had been for some days calm & cloudy.— The color of the water as seen at some distance, was that of a river which has flowed through a red-Clay district: Looking vertically downwards on the sea in the shade, the tint was quite as deep as Chocolate.— It belongs to the family of Trichodes of Bory St Vincent, but does not agree with any of his Species: The sea at this time, I fancy owing to the Calms, abounds to a wonderful degree with various animals.— This fact of sea so very extensively colored by Infusoria appears very curious.—

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Mem: The patches of red sea in the Southern Latitudes owing to the "Whale food" or rather large red Crust. Mac: in great shoals.—