88o 



GENERAL METABOLISM 



[PT. Ill 



that an important factor besides osmotic pressure was the amount 

 of water held back by the protein of the egg-white, the "Auf- 

 quellungswasser". In protein solutions of above 40 per cent, the 

 intensity of this force can reach several atmospheres. In order to 

 penetrate further into these complex relations, Vladimirov mea- 

 sured the electrical conductivity of the egg-white during develop- 

 ment, as an index of what was happening to the electrolytes. The 

 results are shown in Fig. 226. If the eggs were infertile and not 

 incubated, there was no change, the electrical conductivity re- 

 maining in the close neighbourhood of 7-6 . 10^ Kohlrausch units 

 (i K. unit = the conductivity of a substance of which a column 



Kno3 



bo S 

 ho 3 



O w 



•^3 



u 2 y- ff 8 70 72 7'^ 76" 78 20 



Days 

 Fig. 226. 



I c.cm. long and i sq. cm. in area opposes a resistance of i ohm). 

 If the eggs were infertile and yet were incubated, there were only 

 small changes, which led to an increased conductivity, but if normal 

 development went on, there was a marked downward trend, the 

 conductivity reaching a minimum of 2-53 .10^ on the 20th day. 

 These results are in agreement with those of Bellini (see above, 

 p. 830), and would have indicated a definite decrease in the electro- 

 lytes present in the white had not Vladimirov made a correction 

 for the large amount of protein present. This was based on theoretical 

 grounds (see the original paper) and showed, as appears from the 

 dotted line in Fig. 226, that the electrolyte-content really remains 

 constant, i.e. the absorption of electrolytes moves parallel with the 

 absorption of water, and can therefore play little or no part in the 

 mechanism governing the latter phenomenon. Osmotic pressure 



