# Popular Science Monthly/Volume 46/March 1895/Correspondence

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SLEEP AND DREAMS.
Editor Popular Science Monthly:
IN reading Dr. Wurtz's article on the Chemistry 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 number of people in average health is against this proposition; for dreaming is only occasional with them, and is usually considered in the light of a disturbance and as detracting to that extent from the rest and refreshment 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 circumstances the duration of dreamless sleep during the night, even with habitual dreamers, 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 organs 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 inasmuch 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 metabolism, 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 conditions we find in sleep," of which, however, it may be said that it will not bear the scrutiny either of logic or fact. Nevertheless, it does not follow that his article is uninstructive or valueless, for we often find that the errors in a conscientiously thought-out thesis lead to a more thorough understanding 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 Monthly:
In a review of M. Frédéric Houssay'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 desires. 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 Monthly:
I WAS much interested in the article entitled Studies of Childhood, in the January number, but it seems to me that one, at least, of the writer's deductions is too serious. In discussing the child's idea of personal 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 each 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 that during infancy dresses are worn explain this delusion?
* Harriet Heyl Gary.
* Chicago, December 23, 1894.