he secret of their invention. De
Spina was so much pleased with them that he made the invention public.

Monsieur Spoon fixes the date of the invention between 1280 and 1311.
In a manuscript written in 1299 by Pissazzo, the author says: "I find
myself so pressed by age that I can neither read nor write without
those glasses they call spectacles, lately invented, to the great
advantage of poor old men when their sight grows weak." Friar Jordan,
who died in Pisa in 1311, says in one of his sermons, which was
published in 1305, that "it is not twenty years since the art of
making spectacles was found out, and is indeed one of the best and
most necessary inventions in the world." In the fourteenth century
spectacles were not uncommon and Italy excelled in their manufacture.
From Italy the art was carried into Holland, then to Nuremberg,
Germany. In a church in Florence is a fresco representing St. Jerome
(1480). Among the several things represented is an inkhorn, pair of
scissors, etc. We also find a pair of spectacles, or _pince-nez_--the
glasses are large and round and framed in bone.

It was not until 1575 that Maurolicus, of Messina, pointed out the
cause of near sightedness and far sightedness and explained how
concave glasses corrected the former and convex glasses the latter
defect.

In the wake of advanced, education stalks the spectacle age. Any one
watching a passing crowd cannot fail but note the great number of
people wearing spectacles. Unfortunately it is not limited to adults,
but our youths of both sexes go to make up this army of ametropes.

At what age should children first wear glasses? This is a much
debatable question. Where there is simply a defect of vision I should
never prescribe a pair of glasses for a child under ten years of age.
A child under this age runs many risks of injury to the eyeball by
accident to the glasses, and to cut the eye with glass is a very
serious affair. Rather let a child go without study, or even with
impaired vision, than run the risk of a permanent loss of sight.

Another source of evil I must call your attention to, and that is the
indiscriminate use of glasses given by itinerant venders of spectacles
who claim a thorough knowledge of the eye, who make examination free,
but charge double price for glasses.

Persons, before submitting themselves into the hands of opticians,
should know that they are not suffering from any incipient disease of
their eyes. I do not,