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V. Observations on the chemical Nature of the Humours of the 
Eye. By Richard Chenevix, Esq. F. R. S. and M. R. I. A. 
Read November 5, 1802. 
The functions of the eye, so far as they are physical, have 
been found subject to the common laws of optics. It cannot be 
expected that chemistry should clear up such obscure points of 
physiology, as all the operations of vision appear to be; but, 
some acquaintance with the intimate nature of the substances 
which produce the effects, cannot fail to be a useful appendage 
to a knowledge of the mechanical structure of the organ. 
The chemical history of the humours of the eye, is not of 
much extent. The aqueous humour had been examined by 
Bertrandi ; who said, that its specific gravity was 975, and 
therefore less than that of distilled water. Fourcroy, in his 
Systeme des Connoissances chimiques , tells us, that it has a saltish 
taste ; that it evaporates without leaving a residuum ; but that 
it contains some animal matter, with some alkaline phosphate 
and muriate. These contradictions only prove, that we have no 
accurate knowledge upon the subject. 
The vitreous humour is not better known. Wintringham 
has given its specific gravity (taking water at 10000) as equal 
to 10024; but I am not acquainted with any experiments to 
investigate its chemical nature. 
We are told by Chrouet, that the crystalline lens affords, 
by destructive distillation, fetid oil, carbonate of ammonia, and 
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