452 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1957 



peutic effect becomes understandable if one assumes that the pharma- 

 cological effect of salt is that of adrenal stimulation, which results 

 in the improvement of the existing "stress" condition. This theory 

 would be more acceptable if it could be demonstrated that there is 

 some reason for the assumption that a similar mechanism is partly 

 responsible for the salt action in Addison's disease and in adrenalec- 

 tomized animals. In human adrenal insufficiency, the amount of salt 

 required to produce optimal clinical improvement is high, perhaps 

 50-100 times what might be considered "normal" minimum require- 

 ments. Whether these high requirements are only due to the high 

 renal losses or whether they are also needed for their adrenal-stimu- 

 lating effect has not as yet been studied. If the effect were only due 

 to the replacement of losses, one should suspect that the amount just 

 sufficient to bring about equilibrium of the salt balance should allow 

 optimal clinical improvement. Whether the high doses are neces- 

 sary to give equilibrium of the salt balance or whether this could be 

 achieved with much smaller amounts has not as yet been studied. 

 Some very sketchy information obtained on adrenalectomized rats 

 indicated that the salt requirements for maximal improvement are 

 much higher than those necessary to bring about equilibrium of the 

 balance. This point, however, needs more attention in the future. 



Finally, if one asks whether a similar mechanism may also be re- 

 sponsible for the action of salt in adrenalectomized animals, some 

 pertinent data can be uncovered in the literature. As mentioned be- 

 fore, the intestinal absorption of carbohydrate is restored by salt or 

 adrenal hormones. Similarly, fat resorption is improved. Salt or 

 cortical hormones keep hemoglobin formation at normal levels, keep 

 adrenalectomized rats fertile, and prevent cytological changes in the 

 pituitary of adrenalectomized animals. Inasmuch as salt has scarcely 

 a hormonal effect per se, its action may well be mediated by stimula- 

 tion of tissues capable of partly replacing the adrenals. 



The stimulating effect of salt probably sets in motion adaptive 

 mechanisms involving enlargement of the liver, kidneys, and adrenals; 

 this has been found in experimental animals. Similar conditions have 

 been thoroughly discussed in many other "stress" conditions. 



The possible changes, especially perhaps in the emotional sphere, 

 brought on by the stimulating action of salt are, of course, entirely a 

 matter of speculation. The greater responsiveness of people, if they 

 were so stimulated, could have helped throughout the ages in the ac- 

 cumulation of knowledge. Whether this is one of the roots of the 

 reverence which was accorded salt by the ancients can scarcely be 

 guessed at this time. 



It would be of inestimable value if we could be sure how long ago 

 the majority of mankind learned to eat salt. It has been assumed that 



