22 



Bowerbank, J. S. On a New Variety of Vascular Tissue. 8vo. Pampli. 

 London, 1840. 



Queliett, E. T. On the Development of the Vascular Tissue of Plants. 8vo. 

 Pamph. London, 1840. 



On the Structure of some Tissues possessing Hygrometric 



Properties. 8vo. Pamph. London, 1840. 



Emerson, G. B. Notice of Prof. A. P. de Candolle. 8vo. Pamph. Boston, 

 1841. 



Gray, Asa. Notice of the Botanical Writings of the late C. S. Rafinesque. 

 8vo. Pamph. 



Southwick, E. W. Notes of a Tour to the White Hills. 8vo. Pamph. 1841. 



July 1, 1857. 



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



The Report of the Committee appointed to audit the 

 Treasurer's Annual Account was read and accepted. 



Dr. A. A. Hayes reported that a specimen of Gum from Cali- 

 fornia, referred to him at the last meeting, had been examined 

 chemically. It proved to be pure Arabine, or the colorless con- 

 stituent of gums, which is soluble in cold water and forms a clear 

 gum solution, without the character of emulsion. This gum is 

 commercially valuable, the quality being fully equal to any im- 

 ported. 



A specimen of Bark from California, also referred to him, was 

 found to contain mucilage, analogous to that of the bark of the 

 Ulmus fidva, (Slippery Elm.) It was not, however, so abundant, 

 and it was less soluble in water. Besides mucilage, a small por- 

 tion of one of the varieties of tannin gives astringency when the 

 bark is chewed. These are not substances of value, and there is 

 no reason for supposing that this bark will prove specially im- 

 portant. 



Dr. A. A. Hayes exhibited a specimen of Octohedral Tin Ore 

 rom the gold washings of Owen's River, on the way from Mel- 



