54° Transactions of the Canadian Institute. [Vol. VII. 



a striking difference but it is easy of explanation. The proportion of 

 magnesium in sea water is now slowly growing. In the pre-Cambrian 

 oceans it must, therefore, have been very small, not perhaps as low as it 

 is in blood plasma, for in the latter the magnesium would only represent 

 the proportion of an earlier period than that in which the circulation 

 became closed, as the tissues would only reproduce the proportion 

 which had by long accommodation become fixed in them. Even the 

 organisms which live in the sea to-day, whose ancestral forms have lived 

 in the sea since the Cambrian, do not take up the magnesium from the 

 sea water in the full proportion which it has in the latter. 



III. — The Origin of the Relation of the Chemical 

 Elements within Protoplasm Itself. 



There is, therefore, so far as the circulatory fluid of Vertebrates is 

 concerned, a reproduction of the proportions of the sodium, calcium, 

 and potassium of the pre-Cambrian oceans. The problem which now 

 arises is one whose solution involves greater difficulties. If organisms 

 should reproduce in their own circulatory fluids the proportions of the 

 elements in the early geological periods, what contributed to those re- 

 markable proportions which obtain, not in the circulatory fluids, but in 

 the living matter itself? These proportions are widely different from 

 those found in the circulatory fluids, and one cannot bring oneself to 

 regard the former as derived from the latter. In vegetable organisms 

 the potassium and the calcium much exceed the sodium, and even the 

 magnesium may be greater in amount than that of the latter. In 

 animal organisms the proportions are difficult to ascertain owing to the 

 presence of skeletal and other structures in which the calcium and 

 sodium greatly preponderate, but even in these the potassium is nearly 

 equal to the sodium, and in muscle it is greatly in excess, while the 

 calcium and the magnesium are much less than the sodium. Thus, in 

 the muscle of the dog the relative values for each are* : — 



IJVa. K. Ca. Mg. 



loo 354 7.26 25.1 



These proportions may or may not represent approximately those 

 found in unicellular organisms like an Amoeba, or even a white blood 

 corpuscle, but do they represent to any degree the proportions which 

 obtained in the early pre-Cambrian seas when life was represented by 

 unicellular organisms only; which accommodated themselves to the 

 sodium, potassium, calcium, and magnesium in their habitat, just as the 



* Julius Katz, Pflugfer's Arch., Vol. S3. P. '. 1896, 



