File:Quarterly journal of microscopical science (1872) (14803878463).jpg

Identifier: quarterlyjournal121872lond (find matches)
Title: Quarterly journal of microscopical science
Year: 1872 (1870s)
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Publisher: London, J. and A. Churchill (etc.)
Contributing Library: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library
Digitizing Sponsor: Harvard University, Museum of Comparative Zoology, Ernst Mayr Library

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slowness and by diffusion. Thus,several weeks elapse, in most cases, before the formation ofthe calcareous combinations is completed and the experimentterminated. By this method a considerable number of forms are de- • Translated into French from the Dutch original by Professor EdouardVan Beneden, and coirimuuicated by the translator. - A detailed description will be given in a memoir which is about toappear in the publications of the Royal Academy of Amsterdam. It will beshortly sent to press under the title of Researches in Synthetical Mor-phology, on the Artificial Production of Some Organic Calcareous For-mations. ARTIFICIAL PRODUCTION OF CALCAREOUS FORMATIONS. 119 veloped, which are, for the most part, found in organicnature. The most frequently occurring form affected by-calcium carbonate, in combination with albumen, gelatine, orthe other organic substances above mentioned, we willchristen Calcospherites (Fig 1). When the calcospherites are formed in the midst of the Fig. 1.
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liquid, and the surrounding parts are perfectly tranquil,they are perfectly spherical. The dimensions they attainmay vary from -^^TToth to J^th of a millimetre; they becomelarger in proportion as their formation takes place withgreater tranquillity and slowness. The calcospherites oftencontain a nucleus, and all those which attain a certain sizeare seen to be formed of concentric layers and very fineradiating fibres. Similar calcosj^herites, of spheroidal shape,are met with in nature, in the Ibrm of different concretionsdeveloped in the bile, the urine, and the saliva of certainanimals. What is called brain sand of the pineal glandand of the choroid plexus is made up of calcospherites; theotoliths of certain molluscs, worms, and fishes, are calco-spherites ; finally, pearls are calcospherites, which in thecourse of time have attained remarkable dimensions. If the state of equilibrium in the surrounding fluid is notperfect the calcospherites undergo, in the course of their de-velopment

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