. A text-book of human physiology . i:es are muchmore numerous and reach on the average per cu. mm. The white corpuscles are formed in extrauterine life chiefly in the spleenand lymphatic glands: from these issue mononuclear cells (lymphocytes) which,according to some authors, are transformed into polynuclear cells in the bloodstream. Moreover they exhibit a variety of forms and are divided according totheir appearance and staining reactions into several groups (see text-books ofhistology).. Fig. 49. -Hfemin crystals, afterPrever. C. THE BLOOD PLATELETS Discovered by Hayem (1877) and de


. A text-book of human physiology . i:es are muchmore numerous and reach on the average per cu. mm. The white corpuscles are formed in extrauterine life chiefly in the spleenand lymphatic glands: from these issue mononuclear cells (lymphocytes) which,according to some authors, are transformed into polynuclear cells in the bloodstream. Moreover they exhibit a variety of forms and are divided according totheir appearance and staining reactions into several groups (see text-books ofhistology).. Fig. 49. -Hfemin crystals, afterPrever. C. THE BLOOD PLATELETS Discovered by Hayem (1877) and demonstrated in the circulating bloodby Bizzozero and Laker, the blood platelets are spherical or ellipsoidal bodieswhich send out in all directions processes of variable number and length,composed of the same shiny material as the body. According to the investi-gations of Deetjen. Dekhuyzen and others, they have the full value of cells,consist of nucleus and protoplasm, and are capable of amwboid size varies between and mm. Their number, accordingto Brodie and Russel, amounts to about 635,000 in 1 cu. mm. of blood. Withrespect to their chemical constitution it is especially emphasized that theycontain a nuclein body coupled with proteid; and with respect to their physio-logical purpose it is assumed by several authors that they play an essentialpart in the coagulation of the blood. Their origin is as yet conjectural. 154 THE BLOOD § 3. THE PLASMA As already menti


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Keywords: ., bookcentury1900, bookdecade1900, booksubjectphysiology, bookyear1