August 2, 1907] 



SCIENCE 



137 



the ocean. One difSeulty is in getting what 

 may be fairly called the composition of the 

 vital fluid. Ordinary analyses of the blood, 

 for instance, show percentages of phos- 

 phates and an excess of sodium over chlo- 

 rine entirely foreign to sea water, present or 

 past. But when the blood cells and organic 

 matter have been most carefully eliminated 

 the proportion of phosphoric acid drops to 

 but 25 parts per million, and though this 

 is more than occurs in sea water now, it is 

 very much less than occurs in the body gen- 

 erally, and Quinton's supposition that it is 

 due to a small amount of organic matter 

 that one can not get rid of, or that it comes 

 from excretions from the organic matter 

 which the blood is carrying off, is not un- 

 reasonable. We may even, when we look 

 at the analysis of the Sheboygan water, and 

 consider the phosphatic character of the 

 early brachiopods, imagine that there was 

 in early days more phosphorus than the 

 present ocean contains, and that it had been 

 eliminated by life faster than supplied. 



Similar explanations might perhaps be 

 given for the excess of sodium. 



The ratio of sodium to potassium is in 

 the vital medium 10 to 1. In the ocean it 

 is nearer the famous 16 to 1. This is a 

 great contrast to living matter in general, 

 in which potassium dominates over sodium. 



When we come to compare lime and mag- 

 nesia, however, we find that both in living 

 matter in general and in the ocean at 

 present magnesium dominates ^(1.31:0.47) 

 over calcium. On the other hand, in the 

 vital medium there is three times as much 

 calcium as magnesium. This fact did not 

 escape Quinton and Macallum, and they 

 both suggest the same explanation— that 

 there has been an accumulation of mag- 

 nesium in the ocean since it determined the 

 composition of the vital medium. 



This is chemically and geologically very 

 likely. The magnesium salts are more 



soluble than the lime salts. Again deposits 

 from the ocean of lime sulphate and lime 

 carbonate with little or no magnesium, gyp- 

 sum and limestone, are well known. On 

 the other hand, the only common mag- 

 nesium deposit known in the rocks, dolo- 

 mite, has a molecule of calcium for every 

 one of magnesium. Thus a relative in- 

 crease of magnesium over lime seems prob- 

 able. Dubois brings reasons to believe that 

 the ocean is now saturated with calcium 

 carbonate, and has as much as it will hold, 

 and that lime is thrown out, largely in 

 coral and shell, as fast as the rivers bring 

 in carbon dioxide. The magnesium which 

 the rivers bring will readily remain as sul- 

 phate or chloride and is not so easily re- 

 duced or precipitated as calcium sulphate, 

 nor is magnesium so freely taken up and 

 thrown out by organic life. 



Thus while the problem is not a simple 

 one, since it depends on the supply of sul- 

 phur and carbon as well as magnesium and 

 calcium the accumulation of magnesium 

 seems, to say the least, quite possible. In 

 the present ocean Na:Mg:Ca::10.23:1.31: 

 0.47. As regards the sulphur salts, Daly 

 has suggested that, as in the Black Sea so 

 in the early ocean, until the carnivorous 

 habit was well established and a good 

 scavenger system, the sea would tend to be 

 fouled with dead matter and the sulphates 

 brought down by the rivers be reduced and 

 deposited as sulphides, as we find them in 

 black shales and organic limestones. 



No doubt this action has occurred from 

 time to time. It agrees with the customary 

 association of pyrite and black shales, and 

 petroleum and sulphur. But what indica- 

 tions are there of greater frequency of sea- 

 deposited sulphides in the pre-Cambrian 

 rocks? 



Anyway if the accumulation of magne- 

 sium in the ocean depends on the supply of 



