The tissues of the body are adapted to a specific osmotic pressure and as soon as this pressure is exceeded, the substance responsible for the excess is automatically excreted by the kidneys. When this rise in osmotic pressure is due to salt eating the process of excretion is not normally carried out due to the inhibiting effect of salt upon kidney function. Both sodium and chlorine hinder the normal excretion of water by the kidney cells.

The genuine regulatory work of the kidneys can be realized only if we recognize that it depends upon a selective excretion. Salt paralyses the selective excretory action of the kidneys in the same way that it paralyses the selective secretory activity of the endothelial lining of the blood vessels. The excretion of salt by the kidneys is always a tardy process, the salt itself, actually retarding kidney function, although at the same time raising the osmotic pressure throughout the body.

One of the body's regulatory apparatuses is its ability to store toxins and unusable materials in the comparatively inactive tissues--bone, cartilage, connective tissues--pending its elimination at a more favorable opportunity. A favorite site for such deposits is the subcutaneous connective tissue. In heavy salt eaters, especially those with impaired kidneys, a hidden edema (dropsy) and sometimes an edema that is not hidden results from the storing of diluted salt in the subcutaneous tissue. The salt is diluted with water and is held in solution. Some of it escapes in the sweat but much of it remains in the body. Storage of this unusable substance in the less active tissues removes it from the circulation and prevents it from damaging the more vital organs of the body.

A number of competent observers have shown that the isolated administration of water does not promote the retention of water, and the isolated administration of sodium chloride does not promote retention of this salt. Only when these are taken together is there retention of both water and salt. Thus the present practice of taking salt tablets and drinking lots of water (salt creates a demand for more water) assures retention of both. Nothing but harm can come from the practice.

Profuse sweating eliminates much water and some of the salt; much salt is deposited in the clothing and left there as the water evaporates. The salt is not all evaporated and the artificial thirst produced by the salt results in re-introducing an excess of water. The profuse sweating thus produced is enervating.

The use of salt with considerable quantities of water leads to polyuria (frequent urination), while the blood at the same time becomes hydræmic--containing an excess of water. Although urination is frequent under such conditions, only small quantities of water are passed at a time. The frequent urgent desire to void urine is due to a partial paralysis of the sphincter vesicae, produced by the salt.

"Salt-spitting," that is a salty saliva with spitting, is frequently seen in salt users who discontinue its use. This is, no doubt due to the rapid elimination of salt from the tissues that has accumulated therein over a long period of time.