Sponges

SPONGES, Porifera, or Spongiae, are unique animals that form cellular colonies in which there is neither the isolation of organs nor the differentiation of true tissues. Therefore, sponges are recently separated from multicellular animals, Metazoa, into the group Parazoa, contrasting them with all other multicellular animals as Eumetazoa. Very characteristic for sponges are collar flagellate cells (choanocytes), which line either the internal cavity of the sponge or special chambers in the thickness of their walls, communicating with channels both with the external environment and with the internal cavity of the sponge. By the movement of their flagella, these cells drive water from the outside into the sponge, from which water flows out through the osculum. During such water circulation, choanocytes capture microorganisms and particles of nutrients from it. The skeleton of a sponge consists of needles of calcium carbonate or of silicic acid; the remaining mass of the sponge consists of mucus, albuminoid spongin, a small amount of iodine, and various foreign bodies—shells, pebbles, sand, from which the sponge is thoroughly cleansed during processing. Sponges live exclusively in water, are immobile; sponge colonies have the appearance of mushroom-like or tree-like outgrowths of indeterminate form, or conversely, cup-shaped formations, etc. Sponges living in the seas are particularly diverse. They are distinguished as Calcarea (calcareous sponges), Hexactinellida (glass sponges), Tetraxonida, Cornacuspongida (horny sponges), and Dendroceratida. From a biological point of view, the experiments of Morgan are extremely interesting, who rubbed sponges through a silk plankton sieve; through such a mesh passed only individual cells or groups of cells, which after several hours of quiet stay in the water again connected, forming small sponges. This experiment is easily performed with our freshwater sponge, Spongilla. It should be noted the extraordinary ability of our freshwater sponges to develop from small isolated clumps of cells (so-called gemmules), overwintering in the old individual, again into the adult form. In domestic economy, as well as for medical purposes, only sponges containing spongin are used. Sponges are harvested in the Mediterranean Sea, the Atlantic Ocean, and in tropical seas (West Indies). In technical terms, sponges are classified by their size and by the size of their openings. The softest and finest sponges are Euspongia mollissima (off the coasts of Syria), E. communis - common (Marseille) sponge, and E. equina - coarse, with large openings. The latter sponge is not permitted for medical use. Sponges were previously used to stop bleeding, to prevent pregnancy, and for internal use. Now in medicine only disinfected sponges are used. Sponges have important significance as means for washing the body. As contraceptive means, sponges are now almost not used due to their unreliability and inconvenience, and mainly due to the difficulty of selecting and maintaining them in proper cleanliness. The Greek sponge (Euspongia officinalis, in the Mediterranean Sea) is the subject of fishery; its horny skeleton after appropriate processing goes on sale. It was previously used in surgery, and at present is used as a toilet article. In zootechnology and veterinary medicine, it is used for collecting sperm during artificial insemination. From freshwater sponges—Spongilla, Ephydatia, etc.—are used in folk medicine as a therapeutic agent for rheumatism. The action of the needles of Spongilla, which embed themselves when rubbed into the skin, is purely mechanical. Recently it has been proven that some sponges (Spongilla lacustris, Ephydatia fluviatilis) can be classified as cryptotoxic animals, since they contain poisonous substances, the action of which is manifested when extracts and juices from sponges are injected into the abdominal cavity of an animal. White mice and guinea pigs die with symptoms of diarrhea, prostration, and shortness of breath. Per os the poison does not act; the poisonous properties apparently belong to the metabolic products of the sponges (W. Arndt).