354
JOURNAL OF CHEMICAL EDUCATION
FJ~BRIIARY, 1930
permitted. A few doubted the value of any demonstrations not performed by the student himself. 2. The author hoped that many'new experiments and original ways of presenting older experiments would be found in the answers received. In this the results were somewhat disappointing, indicating that colleges, in general, present the conventional list of experiments illustrated in the usual college textbook. There were a few experiments and modified apparatus suggested which will be described in a later paper. The nature of the subject might easily account for the dearth of new demonstrations. A subject such as "The Gas Laws" would undoubtedly bring in many new types of apparatus. 3. Opinion was almost unanimous in that lecture experiments should be short, simple, pertinent, and decisive to be effe6tive. In general, lecture experiments should not duplicate the laboratory experiments. 4. The questionnaire sent out revealed certain weaknesses which should be corrected in any future attempt to secure similar information. It was too long to get the details necessary for proper analysis. A few of the questions were not clear, resulting in ambiguous and indefinite answers. 5. Whether the questionnaire method is the proper way of obtaining information on lecture demonstrations or whether some other method is preferable, the author feels that such information ought to be collected and made available through THISJOURNAL.
Greenest Plants Grow Most Efficiently. Plants whose leaves contain the most chlorophyll, the stuff that makes leaves green, are the most efficient a t the husiness of making new plant tissue-which is, from the farmer's point of view, the chief end and object of plant existence. Ever since pioneer plant physiologists found out what chlorophyll is, and learned that its function is to capture carbon dioxide out of the air and with the help of sunlight to combine it with water t o make sugar, it has been taken for granted t h i t the more chlorophyll a plant has per square inch of leaf surface the faster it can make new stems and leaves. It has remained for Dr. H. B. Sprague and Dr. J. W. Shive of the New Jersey Agricultural Experiment Station to determine the relation accurately, using the exact analytical methods of the chemical laboratory. They have recently reported their results in detail to the American Society of Plant Physiologists. They grew standardized breeds of corn under carefully controlled conditions. They supplied nutrient chemicals a t a known rate. They measured the areas of leaves, extracted the chlorophyll and determined its quantity per square centimeter, and weighed their plants as they harvested them. Correlating their data, they found that the strains with the most chlorophyll per unit area had produced the most cornstalk in a given time. They also found that the plants which produced the greatest spread of leaves were most efficient a t the business of growth. A yellow pigment, carotin, which is found in leaves, bore a similar relation t o the rate of new stalk and leaf production as did the chlorophyll.-Science Sem'ce
