. Senescence and rejuvenescence. Age; Reproduction. 128 SENESCENCE AND REJUVENESCENCE maculata the animals developed from these pieces are about as young physiologically as sexually produced animals of the same size. In P. dorotocephala, where sexually produced animals are not available for comparison, the degree of increase in suscepti- biUty over that of the parent animals is about the same as in F. maculata. Since these results are so completely in agreement, both with expectation and with the results obtained from arti- ficially isolated pieces, experimental records are unnecessary. Stages
. Senescence and rejuvenescence. Age; Reproduction. 128 SENESCENCE AND REJUVENESCENCE maculata the animals developed from these pieces are about as young physiologically as sexually produced animals of the same size. In P. dorotocephala, where sexually produced animals are not available for comparison, the degree of increase in suscepti- biUty over that of the parent animals is about the same as in F. maculata. Since these results are so completely in agreement, both with expectation and with the results obtained from arti- ficially isolated pieces, experimental records are unnecessary. Stages J- ^ ^. Hours 234567 Fig. 35.—Susceptibility of Planaria dorotocephala to KCN mol.: ab, anterior fission-pieces after reconstitution; cd, entire animals before fission. With respect to the anterior fission-piece, however, it is a matter of some interest to demonstrate that the reconstitutional changes occurring in the posterior region of so large a piece as this do alter the physiological condition of the whole piece, including even the head-region. For this reason the record of one susceptibility test of these anterior pieces is given in Fig. 35. For this experiment worms ten to twelve millimeters in length were induced to undergo fission and the anterior fission-pieces were kept without food for twelve days. Another lot of worms of the same size and in the. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Child, Charles Manning, 1869-1954. Chicago, Ill. , The University of Chicago Press
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectreproduction, bookyea
