72 CURRENT TOI'ICS. [J. F. I.

New Method for the Purification of Enzymes.--J. STANLEY KIRK (Jour. of Biol. Chem., 1933, C, 667-670 ) has devised a new procedure for the purification of enzymes, the use of specific anti- enzymes as precipitants. Thus the urease of the soy bean was precipitated from aqueous extracts of that bean by the addition of highly purified antiurease. Washing the precipitate with 0.4 per- cent. sodium chloride solution removes the antiurease. The number of urease units per gram of ash-free solids is increased 850 times by this procedure.

J. S. H.

Relationship of Fluorides in the Water Supply to Mottled En- amel.pFREDERICK S. McKAy (Jour. of Dental Res., 1933, I3, 133- 134) describes conditions in Oakley, Idaho. Formerly the water supply came from a warm spring and contained 6 parts of fluoride anion per million. Persons who used this water supply during the years of enamel development uniformly developed the condition of the teeth known as mottled enamel. Seven and a half years ago, the water supply was changed; the new supply contains less than 0.5 part fluoride anion per million. New cases of mottled enamel no longer occur among the children who have used the new water supply during the period of enamel development. These findings confirm the relationship between the occurrence of this enamel defect and a high fluoride content of the drinking water.

J. S. H.

Apothecaries' Shelfware.--CI~ARLES H. LA WALL AND MILLI- CENT R. LA WALL (.[our. Am. Pharmaceutical Asso., I933, XXII, 334-345) describe a collection of 25 pharmacy jars, now the property of the Philadelphia College of Pharmacy and Science. The earliest items in the collection are of Italian origin and date to the I5th century. The entire collection is of deep interest to the student of ceramics as well as to the student of the history of pharmacy. Of the drugs and preparations mentioned on the labels, a bare half dozen are still used today.