234 



It seems therefore that it is not hy a chemical action, but by a 

 peculiar dynamical influence that light produces contraction of the 

 iris. 



The power of the iris to contract when stimulated by light lasts 

 extremely long, particularly in certain animals. In the eel I have 

 found the muscular irritability of the iris, in one case, lasting sixteen 

 days, during the last winter, in eyes taken out from the orbit. This 

 is an interesting fact, not only on account of the long duration of 

 vitality in the iris, but on account of the conclusion that we are 

 entitled to draw from it, that muscular fibres may be stimulated 

 without the intervention of nerves. In the iris of the eel the nerve- 

 fibres are found very much altered a few days after the extirpation of 

 the eye from the orbit, and they are almost destroyed twelve or 

 fifteen days after this extirpation, i. e. at a time where muscular 

 irritability is sometimes still existing. 



III. A paper was in part read, entitled " Photo-chemical Re- 

 searches. Part. I. On the Measurement of the Chemical 

 Action of Light." By Professor BTJNSEN of Heidelberg, 

 and HENRY ENPIELD ROSCOE, B.A., Ph.D. Communi- 

 cated by Professor STOKES, Sec. R.S. Received November 

 12, 1856. 



November 27, 1856. 



Sir BENJAMIN C. BRODIE, Bart., V.P., in the Chain 

 Dr. Noad was admitted into the Society. 



In accordance with the Statutes, notice was given of the ensuing 

 Anniversary Meeting, and the following names of persons recom- 

 mended for election as Council and Officers for the ensuing year, 

 were announced from the Chair : 



