General physiology; an outline of the science of life . (76), Balbiani (61), Maupas (88), A. Gruber (86, 2),and R. Hertwig (88—89). Paramecium is an oblong infusorian,completely ciliated upon the outside, and constitutes anextraordinarily favourable object for cell-physiological investiga-tions of the greatest variety. Paramascia, visible to the nakedeye, may be cultivated in great quantity in decomposing hay-infusions and may be kept in stock. It is frequently observedthat an epidemic of conjugation suddenly appears throughout thewhole culture, so that almost none but conjugating individuals
General physiology; an outline of the science of life . (76), Balbiani (61), Maupas (88), A. Gruber (86, 2),and R. Hertwig (88—89). Paramecium is an oblong infusorian,completely ciliated upon the outside, and constitutes anextraordinarily favourable object for cell-physiological investiga-tions of the greatest variety. Paramascia, visible to the nakedeye, may be cultivated in great quantity in decomposing hay-infusions and may be kept in stock. It is frequently observedthat an epidemic of conjugation suddenly appears throughout thewhole culture, so that almost none but conjugating individuals arefound. The phenomena of conjugation are as follows:—Two indi-1 Cf. Verworn (90, 1). ELEMENTARY VITAL PHENOMENA 201 viduals apply themselves parallel to one another at their mouth-openings (Fig. 82,1., o), their masses of protoplasm join together toform a bridge, and very characteristic changes in the nuclei above remarked, ciliate Infusoria have two forms of nucleus—•a macronucleus, or chief nucleus, and one or more micronuclei, or. Fig. S2.— Conjugation of Paramacivm in the various successive stages; K, macronucleus; n I. Beginning of conjugation. II. The micronucleus has divided twice insuccession. III. Three of the four portions of the micronucleus perish, the fourth dividesonce more into a male m and a female w nucleus. IV. While the macronucleus is disin-tegrating, the two male nuclei, lm and 5m, become exchanged and unite with the twofemale nuclei into a nucleus, V. t, which divides in turn into f and t. VI. f and t Froni this division arise the rudiments of the new macronucleus pt and the new micro-nucleus nl:. The old macronucleus perishes. (After R. Hertwig.) accessory nuclei. During conjugation the macronucleus perishes,disintegrating and dissolving in the protoplasm. If the Paramce-cium be a form possessing one micronucleus, such as Parametriumcaudatum, where the relations are simplest, the micronucleus ineach indivi
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