286 



Mr. Sprague laid on the table a package of AlgaB, pre- 

 sented to the Society by Mr. B. D. Greene. They 

 formed part of Prof. Harvey's collections, and came 

 from Australia, Ceylon, and the Friendly Islands. They 

 were beautifully prepared with printed labels, and fur- 

 nished another instance of Mr. Greene's liberality to the 

 Society. 



The Corresponding Secretary was instructed to make 

 a fitting acknowledgment to Mr. Greene for the donation. 



The President made some remarks on the mode of 

 reproduction of certain fishes in Surinam, and detailed 

 some interesting points of structure in their eyes. 



Mr. Joseph Tillinghast and Mr. George H. Rogers, of 

 Gloucester, were elected Resident Members. 



November 4, 1857. 



Dr. C. T. Jackson, Vice-President, in the Chair. 



Dr. Jackson exhibited crystals of sugar produced by 

 the Sorghum saccharatum, or Chinese Sugar Cane. They 

 were six-sided prisms, and rhombic prisms with angles 

 of 103° and 77° — crystallographic proof, as he consid- 

 ered, of their being cane sugar. 



Dr. Jackson stated that the young plant contains gum or dex- 

 trine, and glucose. As the period of inflorescence is approached, 

 large quantities of starch globules may be seen in the cells of the 

 plant. If, at this period, the stalk is pressed, the fluid which 

 exudes is found slightly milky, owing to the presence of starch 

 globules, which subside after some time. When the seed ripens, 

 the starch diminishes in quantity in the cane, and the expressed 

 juice gives, upon evaporation, almost wholly cane sugai-. This 

 is a point of interest in the manufacture of sugar. The presence 

 of starch in the syrup prevents the ready formation of crystals of 



