16 
Mr. Henriques, limiting himself to two portions of the wide 
term literature, namely history and fiction, regretted that history was 
not more truthful, and expressed his opinion that the prospects of 
literature were of the very brightest. 
Dr. Ewart reminded the company of the great progress science 
in all departments had made during the last generation, and, speaking 
more particularly with regard to medical science, looked forward 
to great triumphs in the direction not only of curing disease but of 
preventing it. 
Mr. De Paris, whom the Chairman introduced as one of the 
founders of the Society, would not regard art as the least of the three, 
“Literature, Science, and Art,” though it was placed last, and shewed 
the use of art in the study of Natural History. 
The Mayor then proposed “The health of the President,” and 
the toast having been heartily drunk, the Chairman responded in 
appropriate terms. 
Between the toasts the Orpheus Glee Union rendered some glees 
in capital style. 
WEDNESDAY, NOVEMBER [/4th. 
COLOUR BLINDNESS. 
Mr. W. H. REAN, M.R.C.S. 
The questions involved in colour-blindness are not only of interest to 
the scientist and the physician, but also to the student of social life ; 
for what vast issues may depend on the power to discriminate rightly 
the fundamental colour of the spectrum. 
The signalmen on our railways as well as our sailors have thousands 
of lives constantly dependent on their due appreciation of the difference 
between red and green. 
The subject may be conveniently treated under three heads : 
1st : Light and colour in themselves, and theories respecting them. 
2nd : The nervous sense within the brain by which they are distin- 
guished, and 
3rd : Means of testing individual faculties by which colour is 
perceived. : 
Ist : Taking the generally accepted undulatory theory of light as the 
true one, light is due to an infinitely rapid vibratory motion communi- 
cated to the ether and propagated in spherical waves. These trans- 
mitted to the retina call forth the sensation of vision. Newton 
discovered that a ray of white light may be broken up by a prism into 
a series of colours. To this band he gave the name of “spectrum.” It 
was long considered that red, yellow, and blue were the primary colours 
of this spectrum, but of late years the most distinguished physicists 
have pronounced for red, green, and violet. 
