A Guide To The Scientific Knowledge Of Things Familiar Part 94

Q. _Why can we not HEAR in sleep?_

A. Because the drum or "TYMPANUM of the ear" is placid and at rest.

Q. _Why can we not TASTE when we are asleep?_

A. Because the nerves _at the end of the tongue_ (called papillae) are inactive and at rest.

Q. _Why can we not FEEL when we are asleep?_

A. Because the _ends of the nerves_ (called papillae), situated in the skin, are inactive and at rest.

Q. _Why have persons in sleep no WILL of their own, but may be moved at the will of ANY one?_

A. Because the "CEREBELLUM" (or _posterior_ part of the brain) is inactive and at rest.

Q. _Why have DREAMERS no power of JUDGMENT or REASON?_

A. Because the "CEREBRUM" (or _front_ of the brain) is inactive and at rest.

Q. _Why are DREAMS such FOOLISH and INCONSISTENT things?_

A. Because the "PINEAL GLAND" is acting _without the brain_; and the _faculty of thinking_ exists in the "PINEAL GLAND," but the _faculty of judgment_ in the "CEREBRUM of the brain."

The cerebrum of the brain occupies the top and front of the skull. The PINEAL GLAND is a small conical gland (about the size of a pea) _in the brain_.

Q. _Why do some persons LOSE all POWER of SENSATION?_

A. Because the "CEREBRUM" (or _front_ of their brain) _has been injured_.

Q. _Why are many persons IDIOTS?_

A. Because the "CEREBELLUM of the brain" _has been removed_ by some accident, or _injured by some disease_.

The cerebellum is all the posterior part of the brain.

Q. _Why does a person FEEL when he is TOUCHED?_

A. The ends of certain nerves (called PAPILLae) situated in the skin _erect themselves_ when touched, and produce a nervous sensation called FEELING.

Q. _Why are persons able to TASTE DIFFERENT FLAVOURS?_

A. Because the "PAPILLae" of the tongue and palate _erect themselves_ when food touches them, and produce a nervous sensation called TASTE.

Q. _Why do very OLD people LOSE the power of VOLITION, SENSATION, and THOUGHT?_

A. Because their _brain ossifies_; and as the "_cerebrum_" (or _front_ of the brain) goes, they lose the power of _sensation and reason_; and as the "_cerebellum_" (or _posterior_ part of the brain) goes, they lose the power of _volition_.

Q. _Why are OLD people UNABLE to WALK?_

A. Because their _muscles become rigid_.

GLOSSARY.

ACETIC ACID, commonly called Distilled Vinegar.

CITRIC " " Juice of Lemons.

NITRIC " " Aqua Fortis.

OXALIC " " Salt of Lemons.

SULPHURIC " " Oil of Vitriol.

SULPHATE OF LIME " Plaster of Paris.

" MAGNESIA " Epsom Salts.

" SODA " Glauber Salts.

" ZINC " White Vitriol.

NITRATE OF SILVER " Lunar Caustic.

ACETATE OF COPPER " Verdigris.

MURIATE OF SODA " Table Salt.

TARTRATE OF POTASH " Tartar Emetic.

CARBONATE OF AMMONIA " Smelling Salts.

" LIME " Chalk, Marble, &c.

SUPER-ACETATE OF LEAD " Sugar of Lead.

OXIDE OF LEAD " Goulard.

SUBLIMATES are chemical preparations, the basis of which is quicksilver. In CORROSIVE SUBLIMATES, the quicksilver is _extinguished_, either by vitriol, potter's clay, or some other ingredient.

SUBLIMATION is a similar process to distillation; only _solids_(such as metals) are employed, instead of _liquids_.

Thus the fine _blue_ used by painters is a sublimate, and made thus:--Take 2 parts of quicksilver, 3 flower of brimstone, 8 sal ammoniac; and (having ground them) put them with the quicksilver into a gla.s.s retort, luted at the bottom; place the retort in a sand-heat; and (when the moisture is given off) you will have a splendid blue sublimate for painting.

FINISH.