CORRESP ONDENCE. 



697 



CORRESPONDENCE. 



SLEEP AND DREAMS. 



Editor Popular Science Monthly : 



IN reading Dr. Wurtz's article on the Chem- 

 istry of Sleep, in the issue of December, 

 I observe that he considers dreams to be an 

 essential element of " normal sleep." " Sleep 

 so deep as to be dreamless is probably not 

 of the most natural kind. ... No one would 

 claim that natural dreams are symptomatic 

 of morbid conditions," etc. And speaking 

 of the sleep produced by the administration 

 of nitrous oxide with oxygen, he says, " But 

 the lethargy thus produced is dreamless, and 

 therefore not normal sleep.'''' The Italics are 

 mine. 



I think the experience of the larger num- 

 ber of people in average health is against 

 this proposition ; for dreaming is only occa- 

 sional with them, and is usually considered 

 in the light of a disturbance and as detract- 

 ing to that extent from the rest and refresh- 

 ment of the season. And the experience of 

 people who frequently and even " regularly " 

 dream is against it likewise ; for it is certain 

 that an ordinary dream occupies usually only 

 a small portion of the time devoted to and 

 spent in sleep, and that under ordinary cir- 

 cumstances the duration of dreamless sleep 

 during the night, even with habitual dream- 

 ers, is many times greater than the duration 

 of their dreams. 



Then if, as all physiologists are agreed, 

 sleep is in general terms a condition of rest 

 and recuperation, especially of and to the 

 "apparatus of relation" the brain, the or- 

 gans of sense, the voluntary muscles and 

 their associated nervous system it follows 

 that it ought to be dreamless to be entirely 

 effective (and normal). For observe that in- 

 asmuch as, so far as our experience teaches 

 us, there is with us no consciousness without 

 change of condition in some of the matter of 

 our bodies, which means metaholhm, which 

 means destruction of tissue, therefore a given 

 amount of consciousness in dreams (as in 

 waking) cerebral vision, audition, emotion, 

 or what not is at the cost of a certain 

 amount of tissue change, and results in the 

 accumulation in the blood of so much effete 

 matter and gives to the excretory organs so 

 much extra work to do. Both experience 

 and theory are thus shown to be against his 

 position. 



I refrain from criticising in detail his 

 " definition, or rather description, of the con- 

 ditions we find in sleep," of which, however, 

 it may be said that it will not bear the 



scrutiny either of logic or fact. Neverthe- 

 less, it does not follow that his article is un- 

 instructive or valueless, for we often find 

 that the errors in a conscientiously thought- 

 out thesis lead to a more thorough under- 

 standing of the subject than would have 

 been attained had all the propositions been 

 demonstratively true. 



George Pyburn, M. D. 

 Sacramento, Cal., December 20, 1894. 



DO BIRDS CHANGE THEIR FOOD? 



Editor Popular Science Monthlij : 



In a review of M. Frederic IToussay's book 

 on Thrifty Birds, occurring m your October 

 number, page 856, it is said of the California 

 woodpecker that, " though an insect-eater, it 

 stores away for its winter supply food of an 

 entirely different character, nor so subject 

 to decay. It collects acorns for which it 

 hollows small holes in a tree a hole for an 

 acorn into which the acorn is exactly fitted, 

 ready to be split by the strong beak of its 

 owner," etc. 



Now we have the same habit among 

 various woodpeckers here, but the cause is 

 not ascribed to the bird changing its diet, for 

 examination of the acorns shows each one to 

 be infested with a worm or larva which is 

 rapidly fattening. It is this and not the 

 meat of the nut which the woodpecker de- 

 sires. It would seem, then, that 51. Houssay 

 is open to criticism in what he says about 

 " change of diet." F. L. Washburn. 



CoRVALLis, Ore., September 30, 1894. 



STUDIES OF CHILDHOOD. 



Editor Popular Science Montldy : 



I WAS much interested in the article enti- 

 tled Studies of Childhood, in the January 

 number, but it seems to me that one, at 

 least, of the writer's deductions is too seri- 

 ous. In discussing the child's idea of per- 

 sonal identity, he recalls instances in which 

 the child's past self is remembered as of the 

 opposite sex. I myself have noticed this 

 peculiarity a number of times. Now, in eac>i 

 of my examples, as in those cited by the 

 author, it is a boy who refers to himself as 

 having been a little girl. Might not the 

 simple fact thnt during infancy dresses are 

 worn explain this delusion ? 



Harriet Heyl Gary. 



Chicago, December 23, 1894. 



