March, 1932
INDUSTRIAL
AND ENGINEERING CHEMISTRY
trade in 1931. In spite of the fact that chicle was placed on the free list in the middle of 1930, free importations for the whole of 1931 were hardly any higher than for the first half of the year before, when i t was subject to a duty of 10 cents per pound. Last year’s imports reached a total of 8,931,000 pounds valued a t S4,195,000, and those of 1930 were 13,957,000 pounds valued a t 57,022,000. Shellac, chief varnish gum imported, suffered a severe cut in total value which was only $1,953,000 as against $5,190,000 in 1930, but the quantity made a better sho~ving--11,962,000 pounds as against 18,982,000. Xatural camphor scored notably in competition with synthetic, as both the crude and the refined products entered in greater quantities than in 1930, while shipments of synthetic were cut down one-fourth, Imports of natural crude camphor were doubled-2,010,000 pounds as compared with 1,058,000 in 1930-with the total value rising from $419,000 to $716,000, and those of refined rising from 1,032,000 pounds valued at $557,000 in 1930 t o 1,152,000 pounds valued a t $546,000 in 1931. Trade in synthetic camphor fell from 2,405,000 pounds valued a t $851,000 to 1,798,000 pounds valued at $588,000. The value of our exports of naval stores, gums, and resins
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fell off by 37 per cent, totaling only $14,304,000 as compared with $22,698,000 in the year before. The decrease was in evidence both in the trade in rosin and in that of turpentine. Exports of wood rosin, amounting to 154,000 barrels with a value of $1,136,000, were reduced 21 per cent in quantity and 52 per cent in value from 1930; those of gum rosin, 907,000 barrels valued a t $6,923,000, were less by 15 per cent and 42 per cent, respectively, in quantity and value. All the large buyers of gum rosin took reduced quantities, the United Kingdom buying 20 per cent and Germany 15 per cent less. These are our best two customers for this product. Turpentine exports were 12,214,000 gallons last year as against 15,142,000 gallons the year before, the total value showing a somewhat larger decrease, from $6,612,000 t o $4,813,000. The United Kingdom is much the largest buyer of this product, taking 5,020,000 gallons valued a t $1,839,000 in 1930. This represented a decrease of about one-third in quantity and 40 per cent in value from the purchases of the preceding year. RECEIVEDFebruary 4, 1932 All 1931 figures are prehminary, b u t the final figures usually show few changes of importance Further details regarding t h e trade in any particular group of articles may be obtained through thie publication or b y addressing t h e author
YOTES A N D CORRESPONDENCE Toxicity of Ethylene and Propylene Glycols 1;DiTon s NOTE The iol1oa.ing letter was received in June, 1930, b u t the publication wae delayed in t h e hope t h a t further experiments would be made by t h e author. Doctor H u n t states t h a t he has not been able t o pursue his studies further, and, Eince t h e subject is of considerable interest a t t h e present time, t h e letter is now pubiizhed.
Editor of Industrial a n d Engineering Chemistry: Although comparatively little experimental work with ethylene glycol has been reported, the view has long been held that the substance is practically nonpoisonous; its use as a substitute for glycerol in some food and pharmaceutical preparations has been suggested. Recently two deaths in man have been reported [J.Am. M e d . Assocn., 94, 1940 (1930)]from the drinking of an antifreeze mixture consisting of ethylene glycol. Hence it seems desirable to call attention to certain undesirable and dangerous properties of this compound. It has long been recognized that ethylene glycol, Pke other polyvalent alcohols, has little or no narcotic or other immediate obvious actions. It is this lack of immediate effects of even comparatively large doses which has caused a number of experimenters to overlook the inherently dangerous character of the compound. A few years ago I performed a number of experiments with this substance upon rats, mice, guinea pigs, rabbits, cats, and dogs. The compound was administered in various ways-by intraperitoneal and intravenous injections, and by mouth. I t was also added to the drinking water of the animals, and the effects of small doses, continued for several days or weeks, were observed. The compound was found t o be distinctly poisonous. The toxic action was not due to the glycol itself but to one of the products of its oxidation in the body-oxalic acid. The kidneys were very severely injured by the oxalic
acid, and this seemed to be the usual cause of death. Experiments on man have also shown that some of the glycol i s oxidized to oxalic acid. Ethylene glycol proved to be as poisonous as methanol, but in a different way. Of course from a practical standpoint it is a much less dangerous substance than methanol; it is so slightly volatile that there is no danger of poisonous doses being inhaled, and there is no evidence that it is absorbed from the skin. Those who are so foolish as to endeavor to quench their thirst by drinking antifreeze mixtures would probably find other means of committing suicide, but manufacturers should (and apparently do) abstain from adding ethylene glycol to any food product. Used legitimately, this compound is a far less dangerous substance than aniline, benzene, carbon disulfide, turpentine, carbon tetrachloride, and many other chemicals extensively employed in the industries. A considerable number of experiments were performed with propylene glycol; the results were strikingly different from those obtained with the ethylene compound. I could find no indications of a poisonous action. Thus, young rats grew at the normal rate and reached maturity when the only liquid they received was a 5 per cent solution of propylene glycol; rats receiving a similar solution of ethylene glycol died in two or three days, and those receiving a 1 per cent solution frequently died within a week. The propylene compound was well tolerated by animals whose livers and kidneys had been injured by various poisons. It is possible that this glycol may have a true food value in the sense that ethyl alcohol does, and without the drug action of the latter.
REIDHUNT H A R V A RMEDICAL D SCHOOL B O B T O NMaas. , J u n e 19. 1930
