. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. may notbe generally accessible (Penny Cyclopaedia, Art. Siren) the leading facts in it will behere stated. This animal agrees with the Proteus and other species in being peren-nibranchiate (§ 43); and, as in all its congeners yet examined, the blood-discs are ofvery large dimensions. They are usually of an oval form, the long diameter beingnearly twice the short; and the nucleus projects slightly from each of the flattenedsurfaces. Conside
. Principles of human physiology : with their chief applications to pathology, hygiene, and forensic medicine : especially designed for the use of students. may notbe generally accessible (Penny Cyclopaedia, Art. Siren) the leading facts in it will behere stated. This animal agrees with the Proteus and other species in being peren-nibranchiate (§ 43); and, as in all its congeners yet examined, the blood-discs are ofvery large dimensions. They are usually of an oval form, the long diameter beingnearly twice the short; and the nucleus projects slightly from each of the flattenedsurfaces. Considerable variety in the form of the disc presented itself, some of thecorpuscles being much less oval than others; but the nucleus did not partake of thesevariations in nearly the same degree. The nucleus is clearly seen to consist of anumber of moderately-bright spherical granules, of which from 20 to 30 could beseen in one plane or focus, the total number being of course much greater. Whenremoved from the capsule, the nuclei are colourless, and the component granuleshave a high refracting power. Viewed in situ, they present a tinge of colour lighter. PROPERTIES OF THE BLOOD. 415 571. In regard to the form of the blood-corpuscles, it is a fact of muchinterest, that in all oviparous air-breathing Vertebrata they are oval, whilstin Mammalia they are round, with the exception of the family of Came-lidae, in which they are oval. Their form is not unfrequently seen to changeduring their circulation; but this is generally in consequence of pressure;from the effects of which, however, they quickly recover themselves. Inthe narrow capillary vessels, they sometimes become suddenly elongated,twisted, or bent, through a narrowing of the channel; and this may takeplace to such a degree as to enable the disc to pass through an aperturewhich appears very minute in proportion to its diameter.* Even whenwithdrawn from the vessels, however, and floating in their own serum, thediscs are frequentl
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Keywords: ., bookcentury1800, bookdecade1840, bookpubli, booksubjectphysiology
