4 H2O), its sodium salt, AuCl3. NaCl + 2 H2O) and aurum sulfurat. + gold sulphide (Au2S3) are proven, one has attempted to accelerate the slow metal actions and to link them to definite organs. Aurum muriaticum and aurum muriaticum natron are often preferred especially in arteriosclerotic and leutic affections. DOSE The salts and aurum colloidale are usually given in the lower potencies up to the D 6, aurum met. especially with the presence of the mental symptoms also in D 30. ZINC In the periodic system of elements zinc stands in a series related to cadmium and mercury. However the relationship to mercury is not very outspoken either chemically or pharmacologically. Even if one thinks that the working range of zinc is of a much slighter extent than that of mercury, nevertheless considerable similarity in the toxic manifestations is etested that no therapeutic recommendations can be based on them.
Concerning the additional group of the periodic system and the relation of the elements in it in respect to a general survey, the necessary things have already been said (see p. 113ff.). When we designate this class of elements with the term heavy metals, this signifies a characterization a potiori. Because transitions to the light metals of the type of aluminium exist in this group. On the other hand the heavy metals are not limited to the additional group but also appear in the related chief groups (for example, bismuth from whence there is an unclear transition over antimony and arsenic to the non-metals). A universal agreement on the conception of metal is scarcely possible so that it is not feasible to define the heavy metals sharply. The chemical criterion that the metal appear as a cation, the oxides and the metals should be base forming, proves unsuitable because undoubted metals form no bases and others form acids as well as bases. Difficult solubility is also insufficient as a criterion. The conduction capacity for an electro-magnetic stream is best adapted for characterization because it is associated with a special electron structure. But also this obtains only for the so- lid and fluid states of these materials; in the gaseous forms, the “metallic” state diminishes; also too crude for our purpose is the characterization by properties such as impermeability, sheen, etc. In solid state the metals are class I conductors. According to modern conceptions this signifies the presence of freely movable negative electrons within the interspaces of the atoms. These electrons are carriers of electrical conduction; conduction occurs in that the electrons transmit their movement pressure to one another in the same direction (toward the positive pole). Another physical characteristic of metallic elements is that they consist of free atoms which are positively charged (therefore in many typical metal compounds, the appearance of the metal as a cation). The heavy metals are further characterized by their high atomic weight and small atomic volumein contrast to the alkali-earthly alkali-and light metals. The heavy metal tendency increases in single chief groups with the atomic weight.
It should also be constantly held in mind that flowing transitions from all sides occur from the metallic state or the metallic or heavy metal tendency. But here we use the designation heavy metal for the type additional group.
Their physico-chemical mutual nature also conditions a series of common trends in the behavior to the organism. They are poorly soluble and therefore poorly absorbed from the unbroken mucous membrane, with the exception of mercury, which, under the usual conditions, is the only liquid metal. Only from mercury and from a few metal vapors (also removal from the metallic state) are there typical acute intoxications from the intact skin and mucous membranes. The heavy metals precipitate protein irreversibly but mercury albuminate again finds its best conditions for solubility in an excess of protein and salt. Moreover the defense of the uninjured organism fails easiest with lead, but here the persistent absorption of the smallest amounts first brings about a typical chronic metal poisoning. When the metals appear in their ionic forms, as salt solutions (or chromium for example as an acid) in reciprocal action with the organism, the dissociation of the compound, the reaction intensity of the liberated fraction (the acid) decides, whether and how far the local injury conditions the abnormal absorption and the acute poisonous action. These then are comparable to parenteral introduction. Likewise the valence of the metals (for example ferrous of ferric compounds) is important for absorbability.
In most cases the participation of the nervous system will be seen in an intoxication with a heavy metal. These affinities come predominantly to expression if the heavy metal is introduced into the organism in a finely divided form and over a long period, as in the provings on the healthy. Most heavy metals are therefore chronic nerve remedies, iron with its well demonstrated physiological function forming an important exception. The heavy metals appear particularly arranged for this affinity for the nervous system. They are outstanding conductors for electro-magnetic currents; their structure remains unaltered in this conduction (so far as the electron impulse is not altered by the excessive production of heat), therefore they are not destroyed by the conduction. The nervous system is a conducting and connecting system with insulating arrangements that certainly can be placed into activity be electromagnetic energy (light!) and this energy transmission, though perhaps of another type, is still comparable to the well-known electro-magnetic waves. One might advantageously represent in this way how the heavy metals as energy carriers find their receptors in the first line in the nervous system. And now finally must the phenomena be founded, indeed whether it is designated according to ordinal number as affinity, electromagnetically as resonance, in structure, whether it depends upon atom or electron groups, which has something in common in the type and ordinal number of the energy carrier and receiver, so that is may occur. The transference catalysis (comp. p. 115), which we have already discussed as an essential effect mechanism of colloidal heavy metals, is indeed nothing more than the continuation of equal processes up to the dimensions which are available for the experiments of today.
From this chief trend of heavy metals in the organism there are single deviatations in the single effect pictures of the materials of the group. In some the affinity for the nervous system appearance only in chronic poisoning, in chromium (as the chromi- c acid ion) the acid action is directed toward the peripheral parts. With iron there is the physiologically fixed position, as the transference catalysor in cell respiration and this gives the effect picture more a constitutional character than heavy metals have otherwise. So in spite of the narrow neighboring connections of the elements there is a great diversity of the effect pictures, a diversity not only in their symptomatic ramifications but also individually different in their origin and trend.
The element with an ordinal number 26 must be characterized by an extraordinary stability of its nucleus. Its abundance in the earth favors this. Although geologically it is peculiar to the interior of the earth as the chief constituent of the siderosphere and the chalkosphere, its appearance in the lithosphere is very significant, so that in its compounds it amounts to 4.2 Percent of the solid earth crust.
Even in the earth iron acts as an oxygen carrier, ferrous oxide, as it is liberated in the destruction of certain stones and is oxidized to ferric oxide. If now this comes in contact with decomposing organic substances then it oxidized to carbon compounds to carbon dioxide and from ferric oxide, ferrous oxide is again formed (Bunge). In experiments animal charcoal which adsorbs molecular oxygen, O2, cannot oxidize organic compounds without the presence of iron.
PHYSIOLOGIC ROLE OF IRON
The catalytic capacity of iron as transferer of active oxygen to the organic constituents of cells which are not able to react directly with molecular oxygen depends upon the easy change in the valence of iron. This ability to alter valence is indeed one characteristic of the elements of the additional group. In regular sequence the divalent (ferro) iron reacts with O2, changing into the trivalent (ferri) iron and this reacts with the organic substances with liberation of oxygen. Molecular oxygen, O2 is thereby activated to atoms carrying electricity. The catalytic action is limited only to define forms of iron, as they are present in protein compounds in the cells as respiratory ferments (according to Warburg). If this form of cell iron is altered by reaction with a poison as HCN (ferment poison, anticatalysator), then the catalytic capacity of the iron compound ceases.