668 U. S. BUREAU OF CHEMISTRY NOTES. [J. F. I.

The organism causing a pink color in oysters is a yeast-like fungus found in large numbers in and about the oyster house, and occasionally present in oysters before being brolught toI the oyster house. About 3 per cent. of the samples of water from the oyster beds showed the presence of the pink yeast which, however, was never recovered from mud sampiles from the bottom off the bay.

Tests for acid, gas, alcoh.ol, indole and phenol were negative. The yeast inverts saccharose and reduces nitrates to nitrites and ammonia. It produces a pink pigment which is insoluble in water, slightly soluble in alcohol and carbon disulphide, somewhat more soluble in chloroform, and very so’luble in ether. Formalde- hyde gas, I part to 2500 parts of water, kills the yeast.

The greater part of the contamination of oysters’ with the pink yeast occurs during the process of handling in the oyster house. The shell pile of the opening house offers the yeast a favorable place to grow, and when the shells are later deposited on the oyster beds they distribute the yeasts in the water.

To prevent the infection of opened oysters by the yeast, the house and utensils should be washed occasionally through the opening season with a I to 2500 formaldehyde solution (for- malin I to 1000).

PURIFICATION OF BENZOIC ACID BY FRACTIONAL CONDENSATION:

By Max Phillips and H. D. Gibbs.

[ABSTRACT.]

BENZOIC ACID, made by the chlorination of toluene, is con- taminated with small amounts of compounds chlorinated in the ring, the presence of which is most objectionable from the physio- logical point of view when benzoic acid is used in food products. While it is very difficult to remove these compounds by the ordi- nary methods of purification, benzoic acid practically free from chloro-derivatives was obtained in the Bureau of Chemistry by the use of a special apparatus. This apparatus consisted of a vessel in which the crude benzoic acid was placed. The vessel was immersed in an oil bath kept at a definite temperature. A blast of hot air was passed into the crude benzoic acid and the

‘Published in J. Znd. Ecg. Chewi., 12, 277 (1920).

May, 19-w. ] V. S. RITREAU OF CHEMISTRY NOTES. 669

vapors coming off were conducted through a series of chambers, maintained at different temperatures. The least volatile chloro- derivatives separated o’ut in the hotter chambers, whereas the more volatile benzoic acid collected in the colder chambers.

SOME ASPECTS OF THE BEHAVIOR OF CHARCOAL WITH RESPECT TO CHLORINE.

By G. S. Bohart and E. Q. Adams.

[ABSTRACT.]

THIS investigation was undertaken to determine the cause of discrepancies between results obtained by different laboratories for the chlorine capacity of the same charcoals. To study the effect of temperature and humidity of the air stream with which the chlorine was diluted (usually I : IOOO), mixtures of known air, chl’orine, and moisture content were passed through the char- coal which was held in a glass chamber in a constant temperature bath. The chlorine and hydrochloric acid in the outgoing gas were determined from time to time.

In the particular series of charcoals studied, the variation in chlorine-absorbing power between different charcoals was greater than would result from any a,ttainable variation in humid- ity, and the order of the charcoals with respect to absorptive power is not the same as that with respect to apparent density.

The duration of complete chlorine absorption (I ) increases more rapidly than the thickness of the layer of charcoal, (2) passes through a minimum at a temperature between 0” and I2.5O, and (3) at a humidity in the neighborhood of 50 per cent., and (4) is diminished by increasing the flow of air, the rate of supply of chlorine remaining constant. Reductions in pressure up to two feet of water (barometric pressured down to 71 cm. mercury) has little or no e#fect.

For the charcoals studied : Below 12.5 o chlorine appeared beyond the charcoal before hydr’ogen chlorid; above 12.5~ hydro- gen chlorid before chlorine, and the chlorine capacity of the charcoal was increased by one exposure to chlorine followed by heating in vacua to dull redness.

“Published in J. Anz. Chena. SOL., 42, 523-44 (1920).