of the Capsule of the Crystalline Lens and Ciliary Zone. 9 



lain in boiling water till it became quite opake and white, 

 it measured on being taken out 0'65 inch in diameter, and 

 0*55 inch in thickness. In losing in diameter and gaining in 

 thickness, the lens of course acquired a greater degree of 

 sphericity. The alteration in this respect, indeed, was so re- 

 markable, that a gentleman of science, — to whom I showed the 

 two lenses of the same animal after they had been immersed 

 in boiling water, the one with, the other without the capsule, — 

 pronounced without hesitation, that they must have belonged 

 to very different animals. The following Table shows the ef- 

 fects of immersion on the lens of a variety of animals taken at 

 random from a very great number of experiments which I made 

 at different times ; and I can faithfully assure the reader that 

 I have not, in all the trials I have made, met with a single ex- 

 ception to the principle which it exhibits. 



From this Table it is obvious that the change of sphericity 

 produced by immersing the lens in boiling water is due to a 

 contractile power in the capsule alone. By measuring the 

 breadth of the capsular belt above mentioned before and after 

 the immersion, I found that it was rendered narrower as well as 

 shorter by a boiling heat ; and as the transverse circumference 

 of the lens in its capsule was, as nearly as I could determine, 

 the same before and after immersion, this proves the important 

 fact that the contraction of the transverse fibres of the belt is 

 compensated for by an expansion of the elastic membrane con- 

 stituting the rest of the capsule. In order to try to what class 



Third Se?'ies. Vol. 3. No. 13. July 1833. G 



