( 192 ) 
Art. XXXIII . — proceedings of the^ Royal Society of Edin^ 
durgh. 
Nov. 6. 1820. The Royal Society resumed its sittings for 
the ensuing session. 
A paper by Dr Butter was read. On the Spontaneous Dis- 
persion <f Cataracts. In this paper, the author gives an ac- 
count of some caSes that came within his omi observation, where 
the crystalline lens, in its opaque state, disappeared spontaneous- 
ly, independent of any injury or mechanical cause* These facts 
explain the remarkable circtlrilstance of persons having recovered 
their sight without the aid of art. Dr Butter attempted to ac- 
count for the spontaneous dispetsioii of cataracts by the follow^ 
ing considerations. 1. By supposing some change to take place 
either in the quality or quantity of the aqueous humour. Some 
loss of vitality in the lens, in its capsule, or in both, whereby it 
may be cast olf from the surrounding parts. 3. Some morbid 
derangement in the tunic of the vitreous humour. 4. Some vio- 
lent shock, or compression of the eye-ball, by its own muscles, 
of which the patient may not have been sufficiently aware, to' 
refer it to a precise period. 
Nov. 20. — paper by Dr Dyce was read. On the Nature 
and Properties f Alcohol^ and on some Instruments for Mea- 
suring the Specific Gravity of Mixtures f Alcohol and Water. 
Nbv^ 27. — At a General Meeting of the Society, the follow- 
ing Gentlemen were elected Office-bearers mid Counsellors : 
Sir Walter Scott, Baronet, President. 
Right Honourable Lord Gray, I y. ^ 
Hon. Lord Glenlee, / 
Dr Brewster, General Secretary, 
James Bonar, Rsq[. Treasurer. 
James Skene, Esq. Curator of the Museum. 
PHYSICAL CLASS. 
Sir G. Mackenzie, Bart. President. Alexander Irving, Esq. Secretary, 
Counsellors from the Physical Class. 
Dr A. Duncan Dr Hope. 
Gilbert Laing Meason, Esq. Professor Wallace. 
Professor Russell. Henry Jardine, Esq. 
