. A text-book of physiology : for medical students and physicians . tallization and theform of the crystals, but inthe various species of anyone genus the crystals be-long to one crystallographicgroup. From the blood ofthe rat, dog, cat, guinea-pig,and horse crystals are read-ily obtained, while hemo-globin from the blood ofman and of most of the ver- Olk W ^ tebrates crystallizes much ^^^ ^ ^,=,1^ a less easily. Methods for preparing and purifyingthese crystals will be foundin works on physiologicalchemistry. To obtain speci-mens quickly for examina-tion under the microscope,one of the most c
. A text-book of physiology : for medical students and physicians . tallization and theform of the crystals, but inthe various species of anyone genus the crystals be-long to one crystallographicgroup. From the blood ofthe rat, dog, cat, guinea-pig,and horse crystals are read-ily obtained, while hemo-globin from the blood ofman and of most of the ver- Olk W ^ tebrates crystallizes much ^^^ ^ ^,=,1^ a less easily. Methods for preparing and purifyingthese crystals will be foundin works on physiologicalchemistry. To obtain speci-mens quickly for examina-tion under the microscope,one of the most certainmethods is to take some blood from one of the animals whose hemo-globin crystallizes easily, place it in a test-tube, add to it a few dropsof ether, shake the tube thoroughly until the blood becomes laky,—that is, until the hemoglobin is discharged into the plasma,—andthen place the tube on ice until the crystals are deposited. Smallportions of the crystalline sediment may then be removed to a glass* Butterfield, Zeit. f. physiol. Chemie, 62, 173, Fig. 181.—Crystallized hemoglobin (afterFrey): a, b, Crystals from venous blood of man;c, from the blood of a cat; d, from the blood ofa guinea pi&; e, from the blood of a hamster;/, from the blood of a squirrel. GENERAL PROPERTIES! THE CORPUSCLES. 431 slide for examination. According to Reichert, the deposition of thecrystals is hastened by adding ammonium oxalate to the blood inquantities sufficient to make from 1 to 5 per cent, of the man and in most of the mammalia hemoglobin is deposited inthe form of rhombic prisms; in the guinea-pig it crystallizes intetrahedra (d, Fig. 181); in the rat in the form of elongated six-sided plates, and in the squirrel in hexagonal plates. In an elabo-rate and careful study of the crystallographic characters of hemo-globin from a large number of animals Reichert and Brown* haveshown that differences exist between the crystals of various speciesof such a character that
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