Netschajeff[27] subjected 637 school children, well distributed between the ages of nine and eighteen, to the following tests. Twelve very distinct objects were shown them, each for two seconds, which must them be immediately written down. Twelve very distinct noises were made out of sight; numbers of two figures each were read; three-syllable words, which were names of familiar objects, objects that suggested noises, words designating touch, temperature, and muscle sensations, words describing states of feeling, and names of abstract ideas also were given them. The above eight series of twelve each were all reproduced in writing, and showed that each kind of memory here tested increased with age, with some slight tendency to decline at or just before puberty, then to rise and to slightly decline after the sixteenth or seventeenth year. Memory for objects showed the greatest amount of increase during the year studied, and works for feeling next, although at all ages the latter was considerably below the former. Boys showed stronger memory for real impressions, and girls excelled for numbers and words. The difference of these two kinds of memory was less with girls than with boys. The greatest difference between the sexes lay between eleven and fourteen years. This seems, at eighteen or nineteen, to be slightly increased. "This is especially great at the age of puberty." Children from nine to eleven have but slight power of reproducing emotions, but this increases in the next few years very rapidly, as does that of the abstract words. Girls from nine to eleven deal better with words than with objects; boys slightly excel with objects. Illusions in reproducing words which mistake sense, sound, and rhythm, which is not infrequent with younger children, decline with age especially at puberty. Up to this period girls are most subject to these illusions, and afterward boys. The preceding tables, in which the ordinates represent the number of correct reproductions and the abscissas the age, are interesting. Lobsien made tests similar to those of Netschajeff,[28] with modifications for greater accuracy, upon 238 boys and 224 girls from nine to fourteen and a half years of age. The preceding tables show the development of the various kinds of memory for boys and girls: BOYS. Age. Objects Noises Number Visual Acoustic Touch Feeling Sounds Concepts Concepts Concepts Concepts 13-14-1/2 92.56 71.89 80.67 73.00 74.78 75.33 75.44 40.56 12-13 76.45 57.38 72.33 69.67 64.89 73.67 58.67 37.87 11-12 89.78 57.19 70.22 59.67 63.00 73.33 55.33 19.99 10-11 87.12 55.33 49.33 55.11 48.44 57.11 38.33 12.44 9-10 64.00 53.33 49.09 46.58 43.78 43.67 27.22 7.22 Normal 82.2 59.02 64.8 60.6 59.4 64.2 31.2 24.0 value. GIRLS.