Abstract
In a study of the effects of x-rays on animals fed normal dietaries, diets varying in the content of vitamins A and B and diets varying in relative amounts of the basic constituents, protein, fat and carbohydrates, certain findings have been obtained.
As reported formerly, 1 10 MAM (13 “e” units) of x-rays given twice a week to a full grown or growing rat, prolongs and increases growth on a deficient vitamin B ration. 25 MAM (34 “e” units) increase growth and lengthen life on a ration deficient in either vitamin A or vitamin B. On 50 MAM (68 “e” units) the increase in normal growth and length of life is more marked in the series fed a dietary deficient in vitamin A than in one fed a dietary deficient in vitamin B. When larger doses than the above are given, such as 75 MAM (102 “e” units) or 100 MAM (136 “e” units) the life of the animal is shortened on either of these deficient rations. On a balanced laboratory ration life is shortened in each case, the degree of shortening being in direct ratio to the amount of x-rays given. On a stock ration consisting of dog biscuits, lettuce, carrots, meat and corn, the average length of life of a 90 gm. rat with the latter dosage is 90 to 120 days.
As discussed in the communication cited above, these observations indicate that x-rays act to cause a protoplasmic breakdown within the cell. The apparent stimulation with the smaller dose is due to a predominance of the protoplasmic disintegration from which the energy of life is derived. When larger doses of x-rays are given, the greater splitting off occurs between the protoplasm and the ergusia, or vitamin A. With the smaller dose the splitting off occurs between the water soluble elements of the cell and the intercellular substances. In that a high vitamin A dietary does not wholly protect against these larger doses other structural elements of the cell must be destroyed also. This is illustrated by the observation that the usual balanced vitamin dietary protects for a shorter period of time than the well rounded stock ration. 2
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