Con*ta"gious (?), a. [L.
contagiosus: cf. F. contagieux.] 1.
(Med.) Communicable by contact, by a virus, or by a
bodily exhalation; catching; as, a contagious
disease.
2. Conveying or generating disease;
pestilential; poisonous; as, contagious air.
3. Spreading or communicable from one to
another; exciting similar emotions or conduct in
others.
His genius rendered his courage more
contagious.
Wirt.
The spirit of imitation is contagious.
Ames.
Syn. -- Contagious, Infectious. These
words have been used in very diverse senses; but, in general, a
contagious disease has been considered as one which is
caught from another by contact, by the breath, by bodily
effluvia, etc.; while an infectious disease supposes some
entirely different cause acting by a hidden influence, like the
miasma of prison ships, of marshes, etc., infecting the
system with disease. "This distinction, though not universally
admitted by medical men, as to the literal meaning of the words,
certainly applies to them in their figurative use. Thus we speak
of the contagious influence of evil associates; their
contagion of bad example, the contagion of fear,
etc., when we refer to transmission by proximity or contact. On
the other hand, we speak of infection by bad principles,
etc., when we consider anything as diffused by some hidden
influence.
