Chemistry doubles in the total amount of information it amasses every eight years or so, a t present. This poses severe problems in its teaching for, clearly, i t is not possible to include everythiugthough there does not seem to be a lack of trying in the case of some authors and teachers. I n an exaggerated sense we can contrast the text of today with that of thirty years ago. The books are about the same in size. Without attempting to weigh the relative importance of what was taught then and what is taught today, the amount of information, even concepts, then and now are roughly the same. It may he that then one referred only to protons and electrons in the nncleus, whereas now we use other words. But there is conceut in both cases as well as facts, even if less sophist
