The Danish Ingolf-Expedition, Vol. 5 (Classic Reprint)

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Excerpt from The Danish Ingolf-Expedition, Vol. 5The close examination of the Hydrocorallines meets perhaps with more difficulties than the study of the skeleton-bearing Hexacorallia, owing partly to the porous skeleton of the colonies, partly to the delicate nature of the organisms. The characteristics can be determined roughly by means of Dr. Koch's detailed method in which thin sections of the colonies are prepared by grinding with the stained soft parts in situ. The structure of the skeleton can also im'part be studied by breaking the colonies as Hickson (1912 p. 891) seems from the following remark to have done. The way in which it is possible to study the shape of the gasteropore styles is to make a vertical fracture in a plane parallel with the long axis of a branch. In a large percentage of such fractures the whole length of at least one gasteropore with its style will be exposed. It is evident however, that this method is not suited to form the base of a more thorough and systematic investigation of the skeletal parts of the colony. Where it is necessary for the observer to make his results free from chance irregularities he must have recourse to the somewhat slower method of grinding. In the present studies this latter method has throughout been used in the examination of the skeleton. The soft parts are first removed by means *of Eau - de-labarraque, and pieces of the colony have then been ground down on a fine and level Whetstone as far as seemed necessary in each single case. For general systematic work it is usually sufficient to grind down a branch to about its median longi tudinal plane, in a Stylaster, for example, the majority of the gasterostyles will in most cases appear quite free in the middle of the gasteropore. On the finely polished ground surface it will also be possible to study the course of the fine canals. Where there is question of examining the'finer structure of the calcareous skeleton, however, this procedure is not sufficient and it is necessary in addition to have thin sections of the same kind as the geologists use in their studies.About the PublisherForgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.comThis book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully, any imperfections that remain are intentionally left to preserve the state of such historical works.