As mentioned above, potassium is the cation of the cytoplasm, the secondary part of cells, while sodium is the cation of the secondary part of the metazoic compartment, that is of the fluids of this compartment. According to the view presented above, the peculiar distribution of these two cations in the biological realm results from their similar distribution in the environments from which these respective secondary parts, cellular and metazoic, are considered to have been derived. As we related the cytoplasm to mud, respectively to the lithosphere, and the fluids of the metazoic compartment to the sea, we looked for a confirmation of this view in the comparison between the amount of these cations in the two biological compartments and in the two environments which we consider to correspond to them.

Although potassium and sodium are in almost equal amounts in the general constitution of the earth's crust, potassium is found almost entirely in the solid parts while sodium forms the principal constituent of the salts of the fluid part of the earth. The distribution of potassium found between cells and extracellular fluids seems very near to that which exists between lithosphere and hydrosphere. Potassium is found in a proportion of 2.46% of the lithosphere and only in 0.04% of the hydrosphere (201). The ratio of these respective concentrations corresponds to a 1/61 value. This seems near enough to the ratio found in biology. While the extracellular potassium represents only 5 mEq per liter, with a total of 70 mEq (2.7 gm.) for a normal body, the intracellular part corresponds to 115 mEq per liter of cells, with a total of 4,000 mEq (160 gm.) for the body (202). The ratio of 1/59 for total extracellular and intracellular is accepted today although generally considered too high when compared with the previous data given years ago by Shohl (265). This value of 1/59 appears impressively near the ratio of 1/61 found in the comparison of the potassium content of the lithosphere with that of the hydrosphere.

A similar resemblance is encountered when comparing the proportion between sodium and potassium in two fluids: the interstitial fluid of the body and of the sea. The two ratios of these elements appear close enough. For instance, the Atlantic Ocean has 10.464 gm. of sodium per thousand and 0.725 gr. per thousand of potassium, while the Pacific Ocean has 10.233 gr. per thousand of sodium and 0.634 gr. per thousand of sodium (266). The ratios between sodium and potassium are respectively 14 and 16. In the blood serum, the ratio is 16 when the average is considered as 320 mg.% of Na, and 20 mg.% of K. Table XXV shows these comparative values.

Table XXV

(a) Comparison between the Extracellular and Intracellular Potassium and the amount present in Hydrosphere and Lithosphere.

Ratio

Potassium extracellular total body 2.7 gm. ) Potassium intracellular total body 160 gm. )

1/59

Potassium in the hydrosphere 0.04% ) Potassium in the lithosphere 2.46% )

1/61

(b) Potassium and Sodium in the sea and in the body fluids.

Na

K

Ratio

Atlantic Ocean

10.464 gr. 0/00

0.725 gr. 0/00

14.4

Pacific Ocean

10.233 gr. 0/00

0.634 gr. 0/00

16.0

Blood Serum

320 mgr. 0/0

20 mgr. 0/0

16.0

These values seem to bind the distribution of K and Na, seen between the cellular and metazoic compartments, to that which exists between the environments from which we consider these respective secondary parts to have been derived.