The authors gratefully acknowledge Rossy Sandoval, whose dedicated efforts in recruiting minority women to complete risk assessment forms for the Study of Tamoxifen and Raloxifene trial played an important role in making the current analysis possible.

The circumstances of the first determination of the isotopes of lead are given.Washington, D. C.

The Electromotive Force of t h e Reaction HCHO + HCOOH Qualifatix.-Many of the ordinary reactions which we observe each day serve as excellent examples for the study of electromotive force. The work of Acree and his co-workers leads the student of chemistry to regard the common reactions more carefully in accordance with the theory of ionic and molecular reactivity. The physical chemist should no longer believe that only ions participate in each reaction. The theory of Arrhenius and later workers taught us that the ions were the carriers of electrical charges and that it was their function to bring about chemical change. Accepting this view as a partial explanation and adding to this the newer conception of Acree in which the nonionized salts are regarded as an important factor in reactions, might we not suppose that the nonionized part carries a part of the electrical charge in an equilibrium phase such as: NaOC2Hj + IC2Hj h7aOC2H6 + ICzHj + -+ + -C2HjI.NaOC2Ha or C2Hj + INaOC2Hj -e+ XaI + (C2Hs)zO W5thout doubt electromotive force work will aid in studying these rapidly changing systems and complexes, and the accuracy and rapidity of this kind of method will greatly help the investigator to measure these values.

No abstract

To eliminate the viscous torsional discrepancy, it would suffice to use the method developed by Dr. Strouhal and myself, of boiling the wire for 20 or 30 hours in water. Such a wire is then practically free from instabilities at atmospheric temperatures.Finally, since the torque is 0.26s, the deviation angle 0.0017s and the daily detorsion 0.8 = s, it is interesting to notice that energy is being dissipated at the rate of 0.00014 ergs per day, by the decay of torsion (very small as it is) above. Much more, no doubt, is released in the decay of the intense traction. If the body were not exceedingly opaque, the strained metal would probably be phosphorescent.Vitamines are substances of unknown chemical composition occurring in certain foodstuffs, vegetable and animal tissues. They are essential for the maintenance of health and for normal growth of animals and men. The lower organisms also, such as plants and bacteria, seem to require a certain amount of these vitamines for reproduction and growth. The existence of at least three vitamines is known at the present time, namely, the antiscorbutic vitamine, the deficiency of Vich in the diet causes scurvy; the so-called fat'soluble vitamine, occurrng in butter fat and certain other fats; and the antineuritic vitamine, a sufficient amount of which must be consumed by animals and men in order to prevent the disease called beri-beri. All of these three vitamines are essential for normal growth in man.During the last few years a study of the relatiQn of vitamines to growth and the maintenance of health has been a fertile field for biologists. These researches have resulted in conclusions of great scientific and practical value. There can be no doubt, however, that many mistaken ideas have arisen in this brief period, due mainly to a lack of knowledge of the chemical character of vitamines. Thus, a few investigators have attempted to ascribe definite chemical and physical properties to substances which at best were possessed only in their crudest and impure form. These inaccuracies can be attributed only to a lack of fundamental, chemical knowledge on the part of these investigators. Every chemist thinks in terms of solubility, dissociation, and other physical chemical properties, but always only in case of a pure substance or mixtures of known composition and not in the case of crude mixtures and extracts of unknown com-VOL. 6, I1920 3