GEOPHYSICAL LABORATORY. 159 



this independently of any other agencies. Indeed, these inorganic factors 

 must be considered, no matter what be the agency inducing precipitation; for 

 example, there is ground for believing that calcareous organisms are more 

 abundant the more nearly saturated with CaCOs the water is. The view, 

 here advocated, that a somewhat greater role be assigned to the inorganic 

 factors than has hitherto been usual, does not conflict with other views— it 

 merely shifts the emphasis a little; nor does it conflict with any facts that have 

 been definitely ascertained. Its precise importance can be determined only 

 by accurate determination of temperature, salinity, and, particularly, of con- 

 centration of CO2 — free and total — of the water, carried out systematically 

 over the ocean; the results of such an investigation, properly carried out, 

 would have an important bearing on many outstanding biological as well as 

 geological problems. 



(35) An apparent coiTespondence between the chemistry of igneous magmas and of organic 

 metabolism. H. S. Washington. Proc. Nat. Acad. Sci., 2, 623-626 (1916). 



It has been shown that in igneous rock magmas and in minerals magnesium 

 and potassium on the one hand, and iron and sodium on the other, tend to 

 vary together. It is pointed out in this paper that, seemingly, the same 

 relations hold true in the organic world, iron and sodium being essential to the 

 metabolism of animal life and magnesium and potassium to that of vegetable 

 life. This is indicated by the following facts: Hemoglobin and its derivatives 

 (essential to the higher animals in the oxidation processes) are iron com- 

 pounds; and sodium, rather than potassium, is an essential constituent of the 

 blood plasma, while potassium is relatively toxic. On the other hand, chloro- 

 phyll, which is chemically closely allied to hemoglobin, and which is the 

 agent by which most plant life assimilates CO2 from the air, is a magnesium 

 compound, and at the same time potassium is essential to plant life, while 

 iron and sodium are relatively toxic. 



Tliis congruity of these two pairs of elements, both in the mineral and 

 organic worlds, may be simply fortuitous, but it is suggested that it probably 

 depends on fundamental chemical relations, as yet unknown. 



