SCIENCE. 



[Vol. XIII. No. 313 



///. — Work, Disposition. 



1. When is mental labor easiest to you? "In the forenoon," 

 182; "late in the afternoon," 6 ; "at evening and night," 133; 

 " forenoon and evening," 43 ; " no difference," 28. 



2. What is the nature of the work ? The object was to ascertain 

 whether the kind of work limited the time of doing it, but the ques- 

 tion was not successfully formulated. 



3. Do you suffer with nervous disorders (headache, uneasiness, 

 moodiness)? A decided "no" was given only 18 times; "sel- 

 dom," 196; and "yes," 210. 



4. Is your temperament sanguine, choleric, phlegmatic, or melan- 

 cholic? "Sanguine," 132; "choleric," 70; "phlegmatic," 74; 

 " melancholic," 20 ; various combinations, 102. 



The results for the two sexes were so different that they de- 

 manded separation, while the students formed a homogeneous 

 class interesting as a special study. The first problem that was 

 proposed was the relation between the frequency and the vividness 

 of dreams. It appears that 62.5 per cent of those who dream every 

 night dream vividly, 60.5 per cent of those who dream frequently, 

 and only 26.8 per cent of those who dream seldom, showing that 

 the vividness of dreams increases very markedly with their fre- 

 quency. 



Next, how is the intensity of sleep related to the frequency of 

 dreams ? Of the students who dream nightly, 68 per cent have a 

 light sleep (and only 28 per cent a deep sleep) ; of those dreaming 

 frequently, 40 per cent ; of those dreaming seldom, 32.8 per cent. 

 Similarpercentages for the other males are 68.8,42.1, and 39.3; and 

 for women, 72.4, 60, and 50 per cent. We conclude, then, that fre- 

 quent dreams are a concomitant of light sleep, though the relation 

 is far from universal. 



These are the questions that formed the starting-point of the in- 

 vestigation. The rest of the information is grouped together in one 

 large table and an admirably arranged diagram, from which more 

 conclusions can be drawn than can find mention in this risitme. 

 Those that the author singles out may be noted. 



As regards sex, women have 73 per cent of their number dream- 

 ing nightly or frequently, while students have only 50 per cent, and 

 the other males 48 per cent. Again : 63 per cent of the women 

 sleep lightly, and only 42 per cent of students, and 44 per cent of 

 other males. We conclude, then, that women have a very much 

 lighter sleep than men, and that their dreams are proportionately 

 more frequent. 



Another conclusion, the evidence of which is too detailed to pre- 

 sent, is, that as we grow older, our dreams become less frequent, 

 but our sleep becomes lighter ; age affecting the intensity of sleep 

 more than the frequency of dreams. The author regards the stu- 

 dents as in the period of maximum dreaming (twenty to twenty-five 

 years of age). The deep sleep of childhood (hostile to frequency of 

 dreams) is then least counterbalanced by the lessening of dreams 

 due to age. The vividness of dreams shows a similar relation to 

 age and sex : the women dream most vividly ; the students, being 

 younger than the other men, have more vivid dreams. The power 

 of remembering dreams is also dependent upon vividness and fre- 

 quency of dreaming : it is accordingly greatest in women, and 

 greater in students than in more mature men. The liveliness of 

 the emotional nature, a prominent feature of women and youth, 

 seems thus to be marked out as the causative agent in the produc- 

 tion of dreams. 



The duration of sleep should naturally be related to the habit of 

 dreaming, but in the men no such relation can be discovered. In 

 the women, however, it appears that those who dream frequently 

 sleep nearly an hour longer than those who seldom dream. This 

 difference is regarded as due to the fact that men are more under 

 duty to break short their sleep, and thus vitiate the statistics. This 

 is corroborated by the frequency with which the men who dream 

 frequently declare themselves tired in the morning, indicating in- 

 complete sleep. The need of sleep is greater in women than 

 in men ; the duration of sleep being longer, and the percentage of 

 "tired morning and evening" and of "not tired " being 3 to 2 and 

 2 to 3 respectively as compared with the men. Students sleep 

 longer, and are less tired, than other men. 



The time needed to fall asleep is about the same in all three classes, 



— 20.8 minutes for the men, 17. i minutes for students, and 21.2 

 minutes for women. In each case, however, it takes longer for 

 those who are frequent dreamers and light sleepers to fall asleep 

 than persons of opposite characteristics. Eighty per cent of stu- 

 dents sleep uninterruptedly through the night, 70 per cent of other 

 men, and only 43 per cent of women. Light sleep and frequent 

 dreams increase the interruptedness of sleep. 



The power of falling asleep at will is possessed by few. It is 

 greater in youth than in age. Twenty-eight per cent of men, 19 

 per cent of students, and 20 per cent of women sleep in the after- 

 noon, indicating a making-up of insufficient sleep on the part of the 

 men. 



The effect of dream-habits upon mental work is also evident. 

 Those who dream seldom, or sleep deeply, are better disposed for 

 work in the forenoon than light sleepers and frequent dreamers. 

 The forenoon seems in general to be the preferred time of work. 



The statistics regarding nervousness confirm the accepted fact 

 that this is greater among women than men. It is greater among 

 students than among men at large. It is, too, a concomitant of 

 light sleep and frequent dreams. As to temperament, the phleg- 

 matic people are quite constantly deep sleepers and infrequent 

 dreamers. 



Finally, a contrast between teachers and professors of the same 

 average age shows the effect of occupation. The teacher, with his 

 daily toil, has a lighter sleep and more frequent dreams; while the 

 professor, leading a comparatively congenial and worriless life, is 

 a deeper sleeper and a less frequent dreamer. This, perhaps, is 

 related to the lack of visualizing power that Mr. Galton found to be 

 current among men of science. 



The relation between depth of sleep and frequency of dreams, 

 seems explicable on the supposition that the insensitiveness to out- 

 side excitations present in deep sleep, also induces insensitiveness 

 to internal impressions. The threshold of mental life is raised. If 

 the normal psychical activity is great, then, even in a deep sleeper,, 

 will the dreams be frequent, thus accounting for the exceptions. 



In addition to the interesting results that this study has brought 

 out, it increases one's sense of the utility of such mquiries, and 

 shows the truth of Galton's experience, indorsed by the author, 

 that " it is a much easier matter than I had anticipated to obtain 

 trustworthy replies to psychological questions." 



ETHNOLOGY. 

 Jade in Alaska. 

 LlEtJT. G. T. Emmons, who is continuing his interesting re- 

 searches in Alaska, recently made an interesting find at Sitka. He 

 writes : " A bowlder of jade was dug up on the site of the present 

 Indian village, at a depth of some three feet in loose black soil. 

 Two pieces have been cut from it for knives or adzes, each about 



20 centimetres long, from 3 to 4 centimetres wide, and from I to 

 1.5 centimetres in thickness. The three faces on which the bowlder 

 has been cut are highly polished, and show a mottled green sur- 

 face, ranging in color from a yellow green to a rich dark green. 

 After the pieces were cut down on either side, they were broken 

 from the body of the bowlder by a shock, probably by means of a 

 wedge. On another side, where a wedge-shaped adze could be re- 



