. Chemical embryology. Embryology. ii6o THE METABOLISM OF NUCLEIN AND [pt. iii 10-4. Creatinine, Creatine and Guanidine The presence of creatine and creatinine in the unincubated avian egg was at one time a matter for dispute. In 1911 Salkovski and Kojo independently reported the existence of traces of creatinine in the fresh egg, akhough four years before Mellanby had completely failed to find any there. However, there has always been agreement that organised embryonic tissues contain creatine and creatinine. Krukenberg in 1880 detected the presence of the latter substance in the muscle tissu
. Chemical embryology. Embryology. ii6o THE METABOLISM OF NUCLEIN AND [pt. iii 10-4. Creatinine, Creatine and Guanidine The presence of creatine and creatinine in the unincubated avian egg was at one time a matter for dispute. In 1911 Salkovski and Kojo independently reported the existence of traces of creatinine in the fresh egg, akhough four years before Mellanby had completely failed to find any there. However, there has always been agreement that organised embryonic tissues contain creatine and creatinine. Krukenberg in 1880 detected the presence of the latter substance in the muscle tissue of foetal calves at various ages. Later, Mendel &. Days->5 10 Fig. 356. Leavenworth isolated 0-03 per cent, creatine from the muscles of a 265 mm. foetal pig—a low figure, the adult value being 0-45 per cent. Mellanby himself estimated the creatinine in the embryonic chick from the 14th day onwards, and some years later I obtained a series of figures parallel with his, but rather lower. These are shown in Fig. 354. There was little doubt but that the substance was present from the very beginning of development, and in 1924 Tiegs was able to demonstrate it by a colour test in the heart of the 4th-day embryo and in the general body tissue on the 5th day. Still later Fiske & Boyden reported a soUtary value for the 8th day of development, also shown in Fig. 354,. 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 Needham, Joseph, 1900-. New York: The MacMillan Co.
Size: 1919px × 1302px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublishernewyorkthem, booksubjectembryology
