. The microscope and its revelations. tly calcifiedshells of Crustacea ; they occur also in certain imperfect layers ofthe shells of Mollusca ; and we have a very good example of themin the outer layer of the envelope of what is commonly known as a•soft egg,or an egg without shell, the calcareous deposit in thefibrous matting already described being here insufficient to solidifyit. Ill the external layer of an ordinary eggshell, on the otherhand, the concretions ha\e enlarged themselves by Ilie progres-sive accretion of calcareous particles, so as to form a continuouslayer, which consists of,-
. The microscope and its revelations. tly calcifiedshells of Crustacea ; they occur also in certain imperfect layers ofthe shells of Mollusca ; and we have a very good example of themin the outer layer of the envelope of what is commonly known as a•soft egg,or an egg without shell, the calcareous deposit in thefibrous matting already described being here insufficient to solidifyit. Ill the external layer of an ordinary eggshell, on the otherhand, the concretions ha\e enlarged themselves by Ilie progres-sive accretion of calcareous particles, so as to form a continuouslayer, which consists of,-i series of polygonal plates resembling thoseof ;i tessellated pavement. Ill the solid shells of the eggs of the See hi* treatise On the Mode of Formation of the Shell* of Animals, of Bone,and of se\eral other structures, liy a process of Molecular Coalescence, demonstrable Main artificially formed product*, ;.s; and his Further Experiments andObservations in //m-t. Journ. Microsc. Sci. vol. i. Lsoi, p. •2:,.. FIG. 817.—Artificial concretions ofcarbonate of linn-. HARTIXGS CALCO-GLOBULINE I IOI ostrich and cassowary this concretionary layer is of considerablethickness : and vertical as well as horizontal sections of it are veryinteresting objects, showing also beautiful effects of colour under polar-ised light. And from the researches of Professor AV. C. Williamsonon the scales of fishes, there can be no doubt that much of thecalcareous deposit which they contain is formed upon the same line of inquiry has been contemporaneously pursued byProfessor Hartiiig, of Utrecht, who, working on a plan funda-mentally the same as that of Mr. liainey (viz. the slow precipitationof insoluble calcium salts in the presence of an organic colloid),lias not only confirmed but greatly extended his results, showingthat with animal colloids (such as egg-albumen, blood-serum, or of gelatine) a much greater variety of forms may be thusproduced, many of them havi
Size: 1735px × 1440px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectmicrosc, bookyear1901
