In some of the sciences, opinions, either false, or disguised in very fantastical imagery, have prevailed; and the terms which have been introduced during the reign of such opinions, bear the impress of the time. Thus in the days of alchemy, the substances with which the operator dealt were personified; and a metal when exhibited pure and free from all admixture was considered as a little king, and was hence called a _regulus_, a term not yet quite obsolete. In like manner, a substance from which nothing more of any value could be extracted, was dead, and was called a _caput mortuum_. Quick silver, that is, live silver (_argentum vivum_), was killed by certain admixtures, and was _revived_ when restored to its pure state. We find a great number of medical terms which bear the mark of opinions formerly prevalent among physicians; and though these opinions hardly form a part of the progress of science, and were not presented in our History, we may notice some of these terms as examples of the mode in which words involve in their derivation obsolete opinions. Such words as _hysterics_, _hypochondriac_, _melancholy_, _cholera_, _colic_, _quinsey_ {267} (_squinantia_, συνάγχη, a suffocation), _megrim_, _migrane_ (_hemicranium_, the middle of the skull), _rickets_, (_rachitis_, from ῥάχις, the backbone), _palsy_, (_paralysis_, παράλυσις,) _apoplexy_ (ἀποπληξία, a stroke), _emrods_, (αἱμοῤῥοΐδες, _hemorrhoids_, a flux of blood), _imposthume_, (corrupted from _aposteme_, ἀπόστημα, an abscess), _phthisis_ (φθίσις, consumption), _tympanum_ (τυμπανία, swelling), _dropsy_ (_hydropsy_, ὕδρωψ,) _sciatica_, isciatica (ἰσκιαδικὴ, from ἰσκίον, the hip), _catarrh_ (κατάῤῥους, a flowing down), _diarrhœa_ (διαῤῥοία, a flowing through), _diabetes_ (διαβήτης, a passing through), _dysentery_ (δυσεντερία, a disorder of the entrails), _arthritic_ pains (from ἄρθρα, the joints), are names derived from the supposed or real seat and circumstances of the diseases. The word from which the first of the above names is derived (ὑστέρα, the last place,) signifies the womb, according to its order in a certain systematic enumeration of parts. The second word, _hypochondriac_, means something affecting the viscera below the cartilage of the breastbone, which cartilage is called χόνδρος; _melancholy_ and _cholera_ derive their names from supposed affections of χολὴ, the bile. _Colic_ is that which affects the _colon_ (κῶλον), the largest member of the bowels. A disorder of the eye is called _gutta serena_ (the 'drop serene' of Milton), in contradistinction to _gutta turbida_, in which the impediment to vision is perceptibly opake. Other terms also record the opinions of the ancient anatomists, as _duodenum_, a certain portion of the intestines, which they estimated as twelve inches long. We might add other allusions, as the _tendon of Achilles_.