Jeffries.] 94 



and the Calcite also. It was discovered by the donor in 

 September, 1864. 



The Secretary read the Resohitions adopted at the last 

 meeting of the Section of Microscoj^y, by which a permanent 

 organization was effected. 



The following gentlemen were elected Resident Members : 

 Mr. Luther Hills of Chelsea, Rev. E. B. Eddy of Waltham, Dr. 

 Thomas B. Hitchcock of Boston, Mr. Alexander Wadsworth, 

 Dr. James D. Whelpley, Mr. Thomas E. Satterthwaite, Rev. 

 E. ISr. Kirk, Mr. B. F. Campbell, Mr. Charles Whittier, Mr. 

 William Stowe and Mr. E. D. Chamberlin, Jr. 



January 18, 1865. 

 Mr. T. T. Bouve in the chair. 



Twenty-eight members pi'esent 



Dr. B. Joy Jeffries explained his views in regard to the 

 Anatomy and Physiology of Accommodation in the human 

 eye. 



As the eye naturally can only focus parallel rays, or those nearly so, 

 upon its retina, there must be some change in the shape of the eye itself 

 or in its refractive media to enable it to focus divergent rays, or those 

 coming from objects near to. This act of accommodation was thought 

 to be accomplished by pressure of the external muscles altering the 

 shape of the eye, or forcing forward the crystalline lens. Total paraly- 

 sis of all the external muscles not affecting accommodation dis- 

 proves this theory. Some change must therefore take place within 

 the eye itself. Professor Helmholz examined, with an instrument 

 called the Phaciodoscope the three images of a lighted candle, given 

 by the cornea, the anterior, and the posterior surfaces of the lens. 

 This experiment was described by Dr. Jeffries, and the deductions from 

 it explained, namely, that during the act of accommodation the cornea 

 does not change its shape, the lens does not move, but that its shape 

 alters. Its anterior curve becomes greater, pushing forward the edge 

 of the iris forming the pupil, while the outer circle of the iris is pushed 

 back by the aqueous humor. Professor Knapp calculated the effect 



