. Chemical embryology. Embryology. SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 657 the nature of their integration. At present we are only uncovering, as if by a kind of dissection process, the various contributory systems, such as those represented in Murray's diphasic schema for the chick. Shearer found that in i hour i million unfertilised eggs (correspond- ing approximately to 8 mgm. egg nitrogen) consumed 15-1 of oxygen and gave off at the same time 0-067 gm. cal. at standard temperature and pressure. After fertilisation the same quantity of egg-substance consumed 86-4 of oxygen an
. Chemical embryology. Embryology. SECT. 4] HEAT-PRODUCTION OF THE EMBRYO 657 the nature of their integration. At present we are only uncovering, as if by a kind of dissection process, the various contributory systems, such as those represented in Murray's diphasic schema for the chick. Shearer found that in i hour i million unfertilised eggs (correspond- ing approximately to 8 mgm. egg nitrogen) consumed 15-1 of oxygen and gave off at the same time 0-067 gm. cal. at standard temperature and pressure. After fertilisation the same quantity of egg-substance consumed 86-4 of oxygen and liberated 0-3976 gm. cal. heat together with an amount of carbon dioxide equivalent to a respiratory quotient of 0-92. These figures were afterwards gone over again by Rogers & Cole, who desired to introduce even more accurate methods, and to take readings at short intervals over considerable periods of time. Rogers & Cole only published one paper, most of which was taken up with problems of technique. In Shearer's experiments, the vacuum flasks were undergoing a gradual fall of temperature throughout the experiment, and the difference in rate of fall between the control flask and the flask containing the experi- mental material gave the heat- production of the eggs. Rogers & Cole, however, used a dif- ferent method, by which the fall was much slower, and therefore much longer experiments could. Corrected carve Extrapolabion of the ear(y peurt erf the curve be_yoncL 50 minabes Fig. 119. 50 100 Minutes after fertilisation Fig. be carried out. Fig. 119 shows one of their experiments. The total number of eggs used was 3-9 millions. The curve well demonstrates the absence of any variations due to cleavage. In Fig. 120 the average rate of heat-production in calories per hour per million eggs from all their experiments is given. It is probable that not. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readabi
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Keywords: ., bookcentury1900, bookpublishernewyorkthem, booksubjectembryology
