The frontispiece contains the following text, and a portrait of the
author:

Engraved by J. Hopwood, from a picture by J. R. Smith.
THOMAS GARNETT, M.D.
Published March 25th 1800, by Cadell & Davies, Strand.

In line 241 of this text, the word transcribed as too appears as o in
the original text, with blank space indicating the omission of the
first two letters of the word. In Lecture IX of Dr. Garnett's
_Zoonomia_, where the same example of the reaction of the eye to light
is given, the word appears as too.