768 



THE RESPIRATION AND 



[pT. iir 



hatching the embryonic retina produced anaerobically 20 per cent, 

 of its weight per hour lactic acid, but that i year after hatching 

 it produced under similar 

 conditions in the same time 

 65 per cent, of its own weight. 

 This tissue has certainly a far 

 greater glycolytic intensity 

 than any other known, and 

 Cramer suggests that this 

 peculiar property may ac- 

 count for the fact that human 

 epitheliomata and neuroepi- 

 theliomata of the retina have 

 a very short induction-period 

 unlike all other neoplasms. 

 On the other hand the em- 



f 



W 80 120 160 ZOO 2W 280 320 360 WO' 

 — ^TrockengetvicM eines Embryos ( Ratte) 



Fig. 172. 



bryonic lens of the rat was shown by Fujita to have a constantly 

 descending N.G.R. (see Fig. 172). 



Tamiya later made further experiments on the developing liver 

 of the chick. His graph is shown in Fig. 173. It resembles the de- 

 clining glycolytic rate of the rat embryo, and differs entirely from 

 the behaviour of the retina. U. calculated for each stage was negative. 



20 



0,1 0,1 0^ 0,f 0,5 0,6 0.70,8 0,9 1,0 1,1 1,2 1,3 f^ 1,5 1,6 7,7 1,8 1,3 2,0 2,1 2,2 2,3 



Trockengewichf einer Leber /m^r) (Erwachsen) 



Fig. 173. 



i.e. O.G.R. was very low, and the liver-cells at all times during 

 their growth were able to deal with as much lactic acid as their 

 desmolytic mechanism supplied them with. Their metabolism was 

 throughout that of well-organised growth, like that of the rat embryo. 

 Similar work was done by Warburg & Kubowitz on embryonic 

 fibroblasts, epithelial cells and heart cells. The figures are given 

 in Table 91. For the heart, their results agreed well with those of 

 Tamiya for the embryonic liver. As age increased, and the weight 



