July, 1934
I N D U S T R I A 1, A N D E N G I N E E R I N G C H E M I S T R Y
resulted in the extraction of a small quantity of a similar amino acid from a Obtained by Of dried Serum spraying the Serum left from acetic acid coagulation of Some fresh unpreserved latex. Owing to the smaller amount it could not be purified to the same extent, and its melting point was about 20" C. lower than that of the substance obtained here* The rotation in acid Of this impure product was found to be a 3 = ~ 4-6.4'Emil Fischer gives a ' : = t 1 0 . 3 for pure d-alanine hydrochloride.
791
LITERATURE CITED (1) Branch and M i y a m o t o , J. Am. Chem. Sot,, 52, 863 (1930). (2) M c G a v a c k , J., and Rumbold, J. S., IND. ENG.CHEM:., Anal. Ed., 3, 94 (1931). (3) W h i t b y , G. S., Dolid, J., a n d Yorston, F. H., J . Chem. Soc., 1926, 1448. RECEIVED April 4, 1934. Presented before the Division of Rubber Chemistry a t the 87th Meeting of the American Chemical Society, St. Peterrburg, Fla., March 25 t o 30, 1934.
Comparative Toxicity of Fluorine Compounds MARGARET CAXMACK SMITHAND RUTHM. LEVERTON, University of Arizona, Tucson, Ariz.
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they often have to be replaced EPORTS in the literature The use of drinking water containing fluorine by false teeth at an early age. of t h e toxic effects of in concentrations of one part per million or Fluorine compounds are befluorides have been remore is recognized as the cause of mottled enamel, coming more and more comviewed by McClure and Mitchell a defect of human teeth (12, 13, 15). The ( 7 ) and DeEds (4). Such indimonly used as spray insecticides increasing use of fluorine compounds as spray cations of impaired health and in place of arsenicals because the development as subnormal rate toxic action of a r s e n i c a l s is insecticides has prompted this study of the of growth or decline in weight, known and f e a r e d . It would comparat ice toxicity of different compounds of poor appetite and lowered food appear that from the standpoint jluorine. The following compounds of fluorine intake, poor reproduction, and of public health, chronic intoxiare used: sodium, potassium, ammonium, inferior bone and tooth structure cation from fluorides is little to and calcium fluorides; sodium, potassium, and have been r e p o r t e d to result be desired. from relatively low intakes of S o l l m a n n , S c h e t t l e r , and barium fluosilicates; and natural cryolite (soWetzel (17) in 1921 studied the sodium fluoride. High levels of dium aluminum fluoride). A comparison is feeding have caused death. The effect of fluorine intake upon the made of their effect upon growth rate, food conharmful effects resulting from growth and food intake of albino sumption, eficiency of utilization of food, rethe use of rock phosphates as rats. They varied the percentproduction, mortality, and teeth, when supplied m i n e r a l supplements in farm age of pure sodium fluoride in the animal r a t i o n s have been beration from 0.0002 to 0.23 per to young albino rats at the same fluorine conlieved to be due to their fluorine cent for a 1- to 4-monthperiod. centration. U'ide differences in toxicity among content (1, 5 , 10, 18, 19). A c o n c e n t r a t i o n of sodium these compounds are found when the effect upon I n 1931 proof was established fluoride greater than 10 mg. per growth, food utilization, and damage to the in this laboratory (16) that the kg. of rat per day, roughly 0.015 teeth are considered, which may or m a y not be dental defect of h u m a n teeth per cent of the ration, diminished known as mottled enamel (Figfood consumption and growth a reflection of difference in their solubility. ure 1) which is endemic in many even though the food was equally From the standpoint of initial damage to the sections of the world is caused palatable to the animals. Below teeth, hot( ever, all these compounds of fluorine by the toxic action of fluorides this level no harmful effect of are found to be equally toxic. Fourteen parts present in the drinking water the fluoride w a s n o t e d . I n per million of jluorine (from any source) in supply of the afflicted persons. these s t u d i e s , however, only An extensive survey of the congrowth and food consumption the diet of the rats leaces a mark upon the rat ditions in Arizona (13) by means were used as criteria. incisors. The significance of these Jindings in of which the concentration of In 1925 Schultz and Lamb relation to the spray residue problem and human fluorides in water supplies was (11)reported briefly that a level mottled enamel is discussed. correlated with the presence or of 0.1 per cent sodium fluoride absence of mottled enamel and in the r a t i o n interfered with its degree of severity if present, gave evidence that the use of growth rate of rats and that a n "unfavorable effect in redrinking water having a fluorine concentration above 2.7' production begins a t a level of about 0.025 per cent sodium parts per million interfered with normal tooth development. fluoride." I n the same year McCollum, Simmonds, and The drinking of water in the usual amount which contains as Becker (8) reported that, when sodium fluoride was added to little as 5l p. p. m. of fluorine has been found to cause a severe an adequate mixed ration a t the level of 0.05 per cent, the type of mottled enamel of the teeth, the enamel being pitted teeth of rats were observed to be abnormal in appearance and and corroded. Mottled teeth are not only disfiguring in defective in structure. appearance but are so defective in structure and strength that I n this laboratory (14) the feeding of sodium fluoride to rats a t 0.025, 0.05, and 0.1 per cent of the ration has in each case 1 Fluoride determination made by the modified Fairchild ferric chloride interfered with the normal calcification of the teeth to an exmethod deacribed in Ariz. Expt. Sta. Tech. BULL 43 (1932). Unpublished data a t hand now indicate that a concentration of fluorine in water of as tent varying with the Concentration. Even the lowest level little as 1 p. p. m. a8 determined by the Willard or Foster methods of analysis of feeding (0.025 per cent) resulted in defective enamel of a 8 sufficient to cause mottled enamel of human teeth. A concentration of rather severe type of the teeth of rats, dogs, and guinea pigs. 2 p. p. m. is now found to be associated with mottled enamel of the more eevere type. It has been observed also that an effect upon the teeth of the
eqierim~!~itaIanitrials muy he noted whcri growth arid foud intake atid repniduct i o n a r e normal and iio other outward symptoms OS the toxic actio11 of fluorine are evident. It lias alm been noted that fluoriiie fed at the same concentration in the diet in coiribinatim with calcium as caleiolii fluoride has a p p e a r e d to be less toxic t h a n wheii i t wu.s conil~iiied w i t h sodiuni. Tlris pdper reports t i l e w r k rluiic t o e s t a b l i s h Ietlial and cliroiiic toxic Ic~elsOS flumine SUI rats nod to gain informiition rc1at.ir.e to tlie coinparativc toxii!it,? of diBereiit conipouuds of fluoritic, including tlioje in w e as iiisecticides.
Serent curiipounds, the actual percentage of the ditferunt salts in tlre diets was varialile, hut the rations contained fluorine in different coinhinations in concentratious varying from 0.000175 to 1.8 per c a i t of N O MOTTLIN the ration. The rats were k e p t i n individual round galvanized iron cages and given Sood arid water ad liliit,uoi. The ctrcct of the iiigcstiori
