. Chemical embryology. Embryology. SECT. 9] PROTEIN METABOLISM 1105 Table 149. Terroine & Barthelemy Zero hour Faure-Fremiet & Dragoiu Zero hour Faure-Fremiet & Dragoiu Hatching Therefore lost during this time Faure-Fremiet & Dragoiu Loss of yolk-sac Therefore lost during this time Lost during the whole time Protein % wet % dry Milligrams weight weight absolute 27*9 — — 26-5 610 1-1696 23-2 — I-0459 3-3 — 0-1237 c — 0-9000 — — 0-146 0-270 ( %of protein origin- ally present) Consumption of dry solid by amphibian embryos 0 10 20 30 40 Evidently a good deal of the protein m
. Chemical embryology. Embryology. SECT. 9] PROTEIN METABOLISM 1105 Table 149. Terroine & Barthelemy Zero hour Faure-Fremiet & Dragoiu Zero hour Faure-Fremiet & Dragoiu Hatching Therefore lost during this time Faure-Fremiet & Dragoiu Loss of yolk-sac Therefore lost during this time Lost during the whole time Protein % wet % dry Milligrams weight weight absolute 27*9 — — 26-5 610 1-1696 23-2 — I-0459 3-3 — 0-1237 c — 0-9000 — — 0-146 0-270 ( %of protein origin- ally present) Consumption of dry solid by amphibian embryos 0 10 20 30 40 Evidently a good deal of the protein material with which the egg begins is transformed into the protein of the larva, while a smaller amount is combusted. Unfortunately Faure-Fremiet & Dragoiu did not estimate the protein present at the last stage of all, and relied on approximative assessment, but still their data give a general idea of the process as a whole. The other investigators who have studied the chemistry of the developing tadpole have for the most part paid no attention to its protein metabolism. But a notable exception is afforded by the interesting paper of | Bialascewicz & Mincovna which appeared in 1921. These workers estimated both the nitrogen contained in the embryos at different stages and the nitrogen excreted into the circumambient water on each day. Bialascewicz & Mincovna first established the fact that some dry weight is lost by the frog embryo—an important point, for earlier workers had confused the issue by always expressing results in percentages. The data are shown in Fig. 335, in addition to some others collected by Bialascewicz himself in another paper, and by Galloway. Using different temperatures, and consequently different hatching times (68, 78, 90, 96, 100, 120 and 172 hours), Bialascewicz & Mincovna found that the loss of dry solid was always practically identical at. Days 5 10 15 20 25 30 O Rana fu&ca (Bialascewicz) ©Rang sylvatical ® "
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Keywords: ., bookcentury1900, bookpublishernewyorkthem, booksubjectembryology
