210 
HISTOLOGY OF ANIMALS. 
would no doubt receive nearly if not quite as much air 
as the whiter ones. 
There are some rare instances in which pigment is 
secreted in large quantities on the skin of the human 
face. A remarkable case of this abnormal secretion of 
pigment is described and figured by Mr. Teevan in the 
“ Medico-Chirurgical Transactions” for 1844. 
I possess some pigment given me by Mr. Squire, the 
distinguished chemist in Oxford Street, which appeared 
under the right eye of a young woman, and was capable 
of being brushed off with a camel’s-hair pencil. This 
is contained within cells like those of epithelium, and 
consists of granules. Mr. Squire tried various experi- 
ments upon it, and found that he could not remove the 
colour either by the strongest acids or by chlorine. 
Having now arrived at the period when my labours, 
for the present session, must be brought to a close, it 
only remains for me to thank you most sincerely for 
your kind attention, and to express a hope that I may, 
in some measure, have succeeded in imparting such 
knowledge as may be useful in the practice of your 
Profession ; and if so, I shall feel that I have accom- 
plished one of the great objects for which this Institu- 
tion was established, viz. : the advancement of those 
sciences conducive to the alleviation of human sufferings 
and the good of mankind. 
