EVOLUTION TRACED BIOCHEMICALLY 47 



plasm must have adjusted itself to this concentration, which 

 could no longer affect the chromatin, and when evolution 

 had produced vertebrates the cells of such, bathed in a 

 plasma with constant inorganic composition, must have 

 inherited to a certain extent this adjustment. The inorganic 

 composition of such cells may then be regarded as indicating 

 the composition of the ocean water when the nucleus had 

 evolved. 



To ascertain what this composition was, one must take 

 for analysis more or less undifferentiated cells such as 

 amebae, leucocytes and unfertihzed ova of the lower verte- 

 brates. Amebae or leucocytes cannot be obtained in sufficient 

 numbers to furnish material for such analyses, but ova 

 can be used and analyses of those of the common herring 

 gave, in per cent: 



Na K Ca Mg CI 



0.08175 0.1795 0.00458 0.00138 0.2937 



The excess of potassium over sodium (Na:K :: 100:219.9) 

 is in contrast with what obtains in the ocean today, in which 

 the sodium is to the potassium as 100 is to 3.61. That the 

 ocean water of the earhest geological period was much richer 

 in potassium than in sodium is indicated by analyses which 

 have been made of the waters of lakes in regions where 

 nearly all the surrounding surface rocks are of pre-Cambrian 

 origin. The water of Reindeer Lake, situated about 400 

 miles north of Winnipeg, and surrounded wholly by Archean 

 rocks, contains at least twice as much potassium as sodium. 

 So also do the waters of Rachel See, Wiirm See and Ronig 

 See, of the Bavarian Highlands. The ocean water of the 

 Archean must have thus been richer in potassium than in 

 sodium. 



The salts in the ova amount to 0.5609 per cent, or less 

 than one-sixth of the concentration in the ocean of today. 

 If this was inherited, then the animal cell, as such, evolved 

 before the end of the first sixth of the whole geological 

 part of the history of the earth. 



This estimate may not be confirmed when analyses 

 of other undifferentiated animal cells have been made, but 

 so far it is of interest as indicating that after life first began 



