VOL. 4, No. 11
NEW-TYPE TESTS MEET A NEED
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a foundation of r i g h t sense impressions rather than afler. They also aver that a chiid learns to mike correct choices by practice, deading between right and wrong or even true and false. In view of these f a c t s and in no inconsiderable measure supported by the growing use of new-type t e s t s I cannot but conclude that new-type tests are meeting a real need in our teaching procedure.
Note: Readers who may b e interested are referred to Dr. S. R. Powers' Chemistry Test," either Form A or B (The World Book Co., Yonkers-on-Hudson, N. Y.) or H. I,. Gerry's "Tests of High-School Chemistry," either Form A or B (Harvard University Press, Cambridge, Mass.), for examples of t h e new-type tests in high-school chemistry. Similar t e s t s in college chemistry are given by Dr. Hildebrand in an article entitled: "Final Examinations in General Chemistry," THISJOURNAL, 3, 313-8 (March, 1926). "General
Rats Made Immune to Pneumonia. Experiments in immunization against pneumonia by the feeding of add-killed pneumonia germs are being watched with interest by the New York City Department of Health, according to Dr. William H. Park, director of the Bureau of Laboratories. Although the Health Department is taking no part in the experiments it is following carefully the work being done by Dr. Victor Ross of Bloomlield. N. J. With rats for the subjects the experiments have proved successful. The rats were fed pneumonia germs which had been killed by hydrochloric acid. They reacted by building up a resistance to the dead germs which, i t was found, was sufficient to immunize them against injections of living pneumonia germs. It was established further that the age of the rats was no factor in their ability to build up a resistance. Both adult and young rats were used in the experiments and young and old alike were made immune. Because of the success with the rats the experiments will be carried a step nearer the human race and will next be made on monkeys.-Science S d c e Active Part in Tuberculin Protein in Its Nature. The riddle of the chemical nature of tuberculin, the substance used for detecting tuberculosis in cattle, is a step nearer solution through researches reported before the recent meeting of the National Academy of Sciences by Dr. Florence B. Seibert of the University of Chicago. There h e always been a question, Dr. Seibert stated, whether the specifically potent factor is a protein or merely an infinitesimalamount of some very highly active substance attached to the protein. The difficulty in solving problems such as this has been due to the fact that the purification of proteins is one of the most difficult of dl tasks in chemistry. I n her laboratory, however, efforts to obtain a purified product. have succeeded in producing an active protein in crystalline form. One of the surest tests of chemical purity is obtained when crystals come out of a solution; mixed materials do not aystallize. "The crystalline protein is purer and therefore more potent than the original watersoluble fraction of tuberculin from which i t is made," Dr. Seibert said. "One-tenth of a milligram of the original fraction is required to produce a maximum skin reaction in tuberculous guinea pigs, whereas, of the protein obtained from it and recrystallized ten times, as little as four one-hundredths of a milligram sufficedto give an equally strong reaction."-Science Service
