Coming back to the influence exerted by the elements on test manifestations, we found that elements of the same series show some similar properties when acting at a certain level of organization, but some differences appear when they are acting at different levels. Some of these differences are important. Magnesium, calcium and strontium act similarly on the s.d.c. pH, and against convulsions as well. However, magnesium has been found to induce somnolence or even deep sleep in test animals, while calcium immediately wakes them from magnesium induced somnolence. This type of antagonistic action among members of the same series sometimes appears especially pronounced between two consecutive members in the series—for example, between sodium and potassium, magnesium and calcium, oxygen and sulfur, and sulfur and selenium.

Study of this "antagonism" has permitted us to recognize a specific characteristic. When two elements of the same series act upon the same entity, one may substitute for the other. Sodium may replace potassium in cells. Magnesium and calcium, oxygen and sulfur, and sulfur and selenium can replace each other in this kind of reciprocal activity. There is no truly antagonistic action between them. This explains the fact that two elements of the same series, if in sufficient amount can have similar activity at a given level—that of the tissular, for instance, where the changes of the s.d.c. pH take place.

Further analysis of the activity of members of the same series has revealed another important characteristic which has permitted further classification. Differences in activity of members of the same series could be related to the organizational compartments involved. This became clear when activity of members of the I A series was analyzed according to whether these elements form constituents of the metazoic, nuclear or subcellular compartments. Sodium is the predominant cation of the metazoic compartment, which consists of the interstitial fluids, lymph and blood. Potassium is the principal cation of the cellular compartment. Ammonium, which corresponds in most of its properties to rubidium, represents the cation at the nuclear level. It could be seen that the development of hierarchic organization has involved elements with progressively smaller atomic weights.

Study of constituents in compartments and in the environment has further permitted us—as seen above—to correlate the metazoic compartment with the sea, the cellular compartment with the crust of the earth, and the nuclear and subnuclear compartments with the formations in which their constituents were found in the vicinity of volcanoes.

This correlation of the metazoic compartment to the environment of the sea became especially interesting when we could recognize in its constituents not only sodium, but, curiously enough, the other members forming the same period in the periodic chart. Chlorine, magnesium and sulfur, predominant in the sea and also found in the metazoic compartment, are in the same period in the chart as sodium.

We have thus tried to extend the concept of a correlation between the periods of the chart and the different compartments of hierarchic organization. Tentatively we correlated the second period of the chart to the total organism as an entity. Oxygen, carbon and nitrogen—principal elements in air—enter into direct contact with the organism as such. The third period contains sodium, magnesium, sulfur and chlorine, which are found in the sea and can be correlated with the metazoic compartment. The fourth period contains potassium, calcium, iron, nickel, copper, selenium and bromine—all common to the earth's crust—and, according to our tentative systematization, correlated with the cellular compartment. Following the same plan, we could relate the fifth period—containing rubidium, molybdenum, silver, tellurium and iodine—to the nuclear compartment.

As a possible basis for a working hypothesis, we could consider the sixth period—with cesium, barium, gold, mercury, lead, bismuth—and the lanthanium series to belong to a subnuclear or, rather, submorphologic compartment. The seventh period includes the radium and actinium series, characterized by radioactivity. This period could be related to the lowest level of the biological organization, the primary one, probably even the submolecular level. This would relate the intervention of radioactivity— from cosmic rays and especially from the earth's radioactive elements—to the beginning of the biological realm. Such radioactive intervention could have brought together C and N to form N C-N C, which we considered in our hypothesis to be the first entity in the biological realm. This view represents, at least, a new basis for an interesting working hypothesis.

Thus we have the concept of hierarchic compartments related to changing environments. We also can correlate, further, the environments to the periods in the periodic chart to which their principal constituents belong. It is difficult to accept as purely accidental the correlation of the changes in environments with the progressive displacement of their constituents toward periods in the chart with members each time having lower atomic weights. It is in this progression that we can see homotropy developing toward its maximum, complete value. This view, which will be discussed in more detail later, again relates evolution of the biological realm to progress of homotropy, with the environment representing the concrete realization of homotropic evolution.

The entire chart can be considered in terms of hetero and homo series and of periods that correspond to hierarchic compartments, as shown in Table V.

For the moment, the possibility of relating an element, through its membership in a series, to the hetero or homotropic trend and, through its place in a period, to an organizational hierarchic compartment, helps to explain many of the peculiarities seen in the biological distribution of the elements and especially in the role played by them at the "proper" levels to which they belong.

As a general rule, the presence of an element at the level to which it belongs is directly correlated to quantitative optimum values corresponding to the constants of the level and to the qualitative role which it performs. Its presence at levels other than its own must be interpreted in connection with its activity at its own proper level. Increase or decrease in the amount of an element has a different meaning according to the level at which the variation occurs. If it occurs at the specific proper level to which the element belongs, it would indicate a direct quantitative or qualitative change in the activity of the element. At other levels, this is not true. If the activity of an element is qualitatively impaired at its own level, the amount of the element at the immediate superior level will increase. The increase at the superior level can be interpreted as taking place in order to keep at the disposal of the impaired level a sufficient amount of the element for possible later use. On the other hand, an abnormally intensive activity of an element at its own level will reduce the amount of it present at the level immediately superior. The decrease at the upper level can be interpreted as a defensive attempt to reduce the abnormal activity by limiting the supply.

The general rule, which appears to govern the variations in distribution of an element within the organism, makes it important to know the proper level of an element. Some examples will illustrate what we mean. An increase of copper is seen in the blood serum of cancer patients, although a manifest reduction in catalase as well as in copper content is seen in the tumor cells themselves and in the liver cells. According to the view presented above, these findings can be interpreted to reflect a primary insufficiency of copper at its specific level, that of the cell. Copper is quantitatively deficient at the level of the cell not because of its low availability, but because it cannot be utilized well enough qualitatively to form catalase. The qualitative impairment in copper's use at its proper level would lead to an increased amount of copper in the immediately superior compartment, that of the blood serum.