68
JOURNAL OF CHEMICAL EDUCATION
. JANUARY, 1930
be a serious application of electro-organic chemistry in industry until new methods, which are a t present unknown, are brought to light. There is something in these two statements which demands serious consideration by those who are interested in electro-organic chemistry. In the opinion of the writer there apparently is no valid reason for the general neglect of this phase of chemistry on the part of educational institutions, which are primarily interested in the teaching of organic chemistry or of electrochemistry. A valuable tool for the synthetic organic chemist has been almost studiously neglected, from the pedagogic standpoint a t least. But since the literature is now generally available, the author looks forward to great progress in the next decade.
UNKNOWNS FOR QUANTITATIVE ANALYSIS It is possible t o prepare unknowns for quantitative analysis a t the rate of sixty per hour; unknowns in which the instructor can have a high degree of confidence. The method can be illustrated as follows. Let us assume that the members of the class have standardized approximately half-normal acid and base. The instructor measures from a buret, into numbered Erlenmeyer flasks, varying quantities of half-normal oxalic acid, and dilutes to about 50 cc. The method of preparing the unk%owns is explained to the members of the class. The student is instructed to report the volume of halfnormal oxalic acid measured into his flask.
Calcium Phosphorus and Vitamin D Necessary for Good Teeth. To have good teeth that will not decay easily one must eat food that has plentiful amounts of calcium, phosphorus, and vitamin D, Mrs. May Mellanby of Sheffield,England, found as a result of feeding experiments with animals and children. The substances that are necessary for t h i development of gwd teeth are also necessary for the development of good healthy bones, Mrs. Mellanby stated in a recent report to the American Dental Association. In rickets, when the bone development is pwr, the same defects appear in the structure of the teeth. Children suffering from rickets also had many decayed teeth, while in children who were not rachitic, tooth decay was rare, Mrs. Mellanby observed. Oatmeal and maize and other cereals and cereal products are good sources of calcium and phosphorus, but they interfere with calcification, because they contain substances antagonistic to vitamin D, the "toxamins" demonstrated by Mrs. Mellanby's husband, Dr. E. Mellanby. However, if the cereals are irradiated and thus supplied with vitamin D they become factors assisting in the calcification of the teeth, Mrs. Mellanby said.-Science Sewice
