First lines of physiology : designed for the use of students of medicine / by Daniel Oliver.

  • Daniel Oliver
Date:
1844
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Licence: Public Domain Mark

Credit: First lines of physiology : designed for the use of students of medicine / by Daniel Oliver. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    luminous phenomena. Most of the inferior classes of animals which inhabit the sea, as the infusoria, the medusa, the radiaria, the annelides, many of the Crustacea, the mollusca, and even some of the fishes are phosphorescent. The luminous appearance of the ocean, which is frequently observed, particularly in the tropica] climates, is derived from this source. The marine animalcula, contained in a vessel filled with sea water, have been observed to be phosphorescent, whenever the water is agitated by shaking the vessel. Diluted sulphuric acid, poured into a vessel containing luminous animalcula, has been found to occasion a sudden brilliant light, which immediately afterwards disappeared. The phosphorescence of the medusae has been observed to increase whenever the water containing them was warmed. In alcohol, also, their light became more vivid j but this fluid soon killed them, and their phosphorescence disappeared. The phosphorescence takes place during the motions of the animal, and is more vivid in proportion to their vivacity and energy. The light emitted by some of the phosphorescent marine animals, is most vivid at the time of propagation ; and it is asserted by some observers, that even earth-worms are phosphorescent at the period of their amours. A viscid matter exudes from some of the phos- phorescent marine insects, which is also luminous, and which communicates a luminous appearance to the finger, and even to the mouth and saliva of those who eat them. The light disap- pears in a vacuum, but returns on the re-admission of the air. A moderate heat increases its vividness, but the heat of boiling water, or cold, equally destroys it. The phosphorescence continues some time in oil. A dilute solution of muriate of soda, or of nitrate of potash, or the spirit of sal ammoniac, increases its brilliancy; while concentrated solutions, vinegar, wine, alcohol, sulphuric acid, and corrosive sublimate, speedily destroy it. It continues some time after death, but is extinguished at the commencement of putrefaction. Among the animals which live in the air, the tribe of insects furnishes the greatest number of phosphorescent animals. The source of the light in insects, has its principal seat in the posterior rings of the abdomen. It seems to reside in a peculiar albumin- ous matter secreted by the animal, which is phosphorescent when exposed to a moderate heat, and to atmospheric air ; but ceases to emit light when coagulated by alcohol, ether, corrosive sublimate, or concentrated mineral and vegetable acids, &c. The phospho- rescence also disappears in the non-respirable gases, and in a vacuum, but returns on exposure to atmospheric air or oxygen °-as. The phosphorescence usually commences at dusk, and a? an earlier period if the insects be put in a dark place. It seems to be under the control of the animal's will; for a sudden noise will sometimes instantly cause it to cease. Some naturalists attribute the phenomenon to the action of the nerves ; others to the faculty possessed by insects of accelerating or retarding their respiration,