Oct., 1922
THE JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
cerevisiae, which has been in use a t the Forest Products Laboratory for several years and has proved very efficient in the fermentation of sugars resulting from the hydrolysis of wood. The sugar solutions were prepared for fermentation by evaporating to a suitable concentration and then adding a sufficient quantity of 10 per cent solution of autoZgyzed yeast to make the whole correspond to a 2 per cent yeast solution. The yeast water was prepared according to the method of Fred and Peterson by boiling autolyzed yeast with distilled water for one hour and filtering while hot. The solution was then again boiled, filtered, and finally sterilized in an Arnold steam sterilizer.
DISCUSSION OF RESULTS I n the fermentation of the sugars resulting from the autoclave cooks of the extracted residue no precautions are necessary other than those already de~cribed.~I n order to obtain a satisfactory fermentation of the solutions containing galactose, however, it is imperative that the temperature and acidity be carefully regulated. The temperature must be held between 85" and 90" F., and the initial acidity of the solution not greater than 5". If the acidity is greater little or no fermentation takes place. When the galactose solution is fermented alone, but very little increase in acidity occurs as the fermentation progresses, but when the solution re-
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sulting from the hydrolyzed wood is fermented, an increase of 4" acidity is quite common. I n view of the difficulty formerly encountered in the fermentation of galactose, it is quite surprising that such good results are obtainable under the conditions outlined in this paper. I n all cases the fermentation took place better in the galactose solution than in the liquor containing the mixed sugars. In Expt. I1 the minimum total yield was 35.95 gal. of 95 per cent ethyl alcohol per ton of dry wood, while the maximum was 42.9 gal. The average yield from this was 39.9 gal., by far the largest yield of alcohol obtained from any wood. I n Expt. 111, in which the mixture sugars were used, the average yield was 33 gal. of 95 per cent ethyl alcohol per ton of dry wood. This lower yield is no doubt due to the greater acid-forming tendency of the sugars other than galactose, with a consequent inhibition of the yeast in the fermentation of the latter sugar. Even in this case the yield was almost 10 gal. greater than from any of the woods previously studied. The fact that galactose from western larch can be fermented readily with the production of ethyl alcohol is particularly interesting from the standpoint of the paper-maker, since by an extraction of his chips with water before pulping a quantity of sugar is obtainable that is easily convertible into ethyl alcohol.
Radioactivity of Miscellaneous Waters Examined in the Bureau of Chemistryl'' By W. W. Skinner and J. W. Sale WATERAND BEVERAGE LABORATORY, BUREAUOF CHEMISTRY, DEPARTXENT OF AGRICULTURE, WASHINGTON, D. C.
From the experience of the Bureau of Chemistry, in analyzing commercial boitled waters of natural origin, and from published data, it may be concluded that shippers of these products are not justified in making any statements on the labels which will induce prospectiw consumers to purchase the articles because of their radioactioity.
T
H E ENFORCEMENT of the Federal Food and Drugs Act of 1906 necessitates the examination of mineral waters and other products for content of radioactivity. Consequently the Water and Beverage Laboratory was equipped with three electroscopes of the emanation type, an alpha-ray electroscope, the apparatus designed by Boltwood8 for separating and collecting emanation, and other apparatus necessary for making analyses of the radioactivity of various products. This equipment, the methods used in calibrating the electroscopes, determining the radioactivity of samples, and reporting results have been described in a previous communication4 from this laboratory. Foreign and domestic bottled mineral waters, pads, ointments, capsules, sediments, and other products classified as dru s, coming within the jurisdiction of the Act, are examined, if t eir labels bear statements relating to radioactivity. In addition to official samples of this nature, the laboratory
a
1 Presented before the Division of Water, Sewage, and Sanitation at the 6lst Meeting of the American Chemical Society, Rochester, N. Y.,April 26 t o 29, 1921. 2 Published with permission of the Department of Agriculture. a Phil. Mag., [61 9 (1905),599; A m . J . Sci., [4]18 (1904),378. 1 "Determination of Radioactivity," J . Assoc. Oficial Agr. Chem., a (1916-17), 116.
has examined a few spring, river, lake, and ocean waters collected by Bureau representatives for the purpose of obtaining data for use in litigation. In the examination of bottled waters, it is usually sufficient to determine the activity as received, in which case before removing the stopper the sample is chilled, opened, the contents acidified, and poured carefuIly into the boiling-out flask. Agitation of the water is avoided after the sample is received in the laboratory. Ordinarily, no attempt is made to determine the activity of the gas in the neck of the bottle, since only the emanation or radium salt, dissolved or suspended in the water, is consumed. As we have usually no knowledge of the exact time when the water is bottled, it is obviously impracticable to calculate the initial activity of the water a t source by using the accepted formula which represents the rate of decay of emanation. We do make this calculation, however, on samples collected from source for investigation purposes when adequate precautions are taken. It is desirable sometimes to determine whether or not activity is due to the preeence of radium salts dissolved or suspended in the water, in which case the permanent activity is determined in the ordinary manner. In the accompanying table, the results have been expressed in grams of radium x 10-9 per liter, corresponding to activity found. This unit is known also as millimicrogram, and is one billionth of a gram. The letter I in the column of results means that the time of collection of the sample was known and the initial activity, I, of the sample has been calculated; R indicates that the value in the table represents the activity of the sample as received in the laboratory, which may or
