C 2 0 
I'll. Some Facts relative to the late Mr. John Hunter s prepa- 
ration for the Croonian Lecture. By Everard Home, Esq. 
F. R . S.. 
Read November 14, 1793. 
Mr. Hunter having announced to the Royal Society that 
he would make the structure of the crystalline humour of the 
eye the subject of the Croonian lecture for the present year, 
and having, unfortunately for science, died before his observa- 
tions on that subject were rendered complete, I feel it a duty 
I owe to his memory, as well as to the Society, to state the 
facts respecting this humour with which he had acquainted 
me ; and shall subjoin an unfinished letter from Mr. Hunter 
to Sir Joseph Banks on the same subject. 
It is now many years that Mr. Hunter has had an idea, 
that the crystalline humour was enabled by its own internal 
actions to adjust itself, so as to adapt the eye to different dis- 
tances ; and when the Tania hydatigena first came under his 
observation as a living animal, he was surprised to see the 
quantity of contraction that took place in a membrane devoid 
of muscular fibres, but made use of the fact in his investiga- 
tion of the structure of the crystalline humour of the^eye. 
Some time after this, having occasion to dissect the eye of 
the cuttle-fish, which he had frequently done before, but not 
with exactly the same view, he discovered in the crystalline 
