J. Ernestine Becker

The Effects of Strontium Administration on the Histological Structure of the Teeth of Rats

The effects upon the animal organism of the feeding of strontium salts has been studied by a number of workers. Stoeltzner (1908) and Lehnerdt (1910) have reported that the feeding of strontium salts results in the production of excessive amounts of osteoid tissue in the bones. Shipley, Park, McCollum, Simmonds, and Kinney (1922) reported similar findings. They used McCollums diet 2581 as a basal one, which is composed as follows:

Effect of Ether Peroxides in Wheat Germ Oil on Production of Tumors in Rats

Rowntree and associates 1 have reported a high incidence of abdominal sarcoma in Wistar rats, as well as albino rats from the Buffalo and Yale strains, when fed crude wheat germ oil prepared by ether extraction. Great variability occurred in the rate of tumor production. In rats given 1 cc of oil daily tumors appeared in about 100 to 200 days; with 4 cc daily the average was about 54 days. The nature of the neoplastic agent has not been determined but since it appears to be absent from refined ether-extracted wheat germ oil, and wheat germ oils not obtained by means of ether, it is possible that the factor is produced by some action of ether on wheat germ. Owing to the tendency of unsaturated fatty compounds to undergo oxidation while in contact with ether containing peroxides 2 it appeared to us that the neoplastic agent might have arisen through the action of such peroxides, formed in the extraction of wheat germ with ether, although the latter was reported to be peroxide-free before it was used. We have tested this hypothesis as follows: Two volumes of C. P. peroxide-free anhydrous ether were added to one volume of fresh cold pressed wheat germ oil∗ in a glass flask fitted with a condenser. This oil was aerated seven hours by means of a slow current of air drawn through H2SO4 and glass wool. The mixture was allowed to remain in the flask at room temperature for 36 hours, without protection from light, after which most of the ether was removed by distillation at atmospheric pressure. The mixture was then placed in an evaporating dish and heated on a water bath for 2 to 3 hours, with occasional stirring to remove most of the ether that remained.

Toxicity of MnCl2.4H2O when Fed to Rats

Findlay 1 claims that addition of manganese chloride to the “ordinary” diet of rats produces cirrhosis of the liver and death in from 6 to 10 weeks. He fed 0.3 to 0.4 g manganese chloride per rat per day but failed anywhere to indicate the composition of the diet used. McCarrison 2 fed rats 0.889 mg of MnO per day. He compared their weights with those of a similar group receiving no manganese other than that contributed by the salt mixture and the other constituents of the diet. He states “There was no difference in the percentage weight curves of the 2 groups up to the 32nd day. Thereafter the curves diverged gradually and increasingly; that of the group receiving manganese being at the lower level.” The experiment lasted 135 days. To another group of rats he fed MnCl2 at a level of .0327 mg per rat per day. A control group received no MnCl2. He states, from the outset the rate of growth of the group receiving 0.327 mg MnCl2 daily per rat surpassed that of the control group.” The experiment lasted 53 days. Unfortunately, the diets used in these 2 sets of experiments were not identical either in the source of the manganese, amounts of manganese, or sources of fat or vitamins. Orent and McCollum3 demonstrated the need of the rat for manganese for normal reproduction. On manganese-free diets females fail to suckle their young, and males show testicular degeneration after 100 days or less. The addition of .005 to .05% manganese in the form of MnCl24H2O promotes normal functioning of males and females. As a result of these observations further experiments were conducted where manganese was added to the blasal ration at the following levels of MnCl2.4H2O: 0.18%, 0.36%, 0.9%, 1.8%, 3.6%. Thus there was added to the diets .0499, .0998, .2495, .4990, and .9980 g of manganese respectively. Thle basal ration had the following composition: Table