(55^ 



TANNING MATERIALS 



Tanning materials are employed in changing animal 

 skins into leather. This is chiefly the effect of the tannic 

 acid contained in the agents upon the tissues of the skin, 

 but another important action is that of filling up the 

 minute cavities of the skins, to make the leather firm and 

 compact. 



THE PINE FAMILY {Pinaceae) 



1324. Hemlock bark. — The bark of Tsuga canadensis (L.) Carr. Native of eastern 



North America. Collected in the New York Botanical Garden by P. 

 Wilson in July, 1899. 



1325. Episcia bark. — The bark of Picea Abies (L.) Karst. Native of Europe. 



From Hungary, through the Paris Exposition of 1900. 



1326. Another sample of the same, of best quality. 



1327. The same, of second quality. 



1328. The same, ground and ready for use. 



1329. Pino bark. — The bark of a Spanish species of Pinus, or pine, ground and 



ready for use. 



1330. Saw-palmetto trunk. (See number 391.) Collected at Miami, Florida, in 



1904, by J. K. Small. 



133 1. The same, ground ready for extraction. 



1332. Saw palmetto extract. — A tanning extract prepared from the preceding. 



1333. Spent saw-palmetto wood. — The ground wood after the extract is removed. 



1334. Saule. Willow bark. — The bark of Salix acutifolia Willd. (Salic ace ae — 



Willow Family). Native of northeastern Asia. From Russia, through 

 the Paris Exposition of 1900. 



1335. The same, in a ground condition. 



1336. French saule. — The bark of a French species of Salix. From the Paris 



Exposition of 1900. 



1337. Aune, or alder bark. — The bark of a species of Alnus, probably A. glutinosa 



(L.) Medic. (Betulaceae — Birch Family). Native of France. From the 

 Paris Exposition of 1900. 



THE BEECH FAMILY (Fagaceae) 



1338. Rock, or white, chestnut-oak bark. — The bark of Quercus Prinus L. Native 



of eastern United States. Collected at Mount Airy, North Carolina, June 

 20, 1909, by H. H. Rusby (see Herb.). 



1339. Another sample of the same. Collected by H. H. Rusby at upper Montclair, 



New Jersey, July 3, 1919. 



1340. Chene. — The bark of an oak, probably Quercus Robur L. Native of Europe. 



From France, through the Paris Exposition of 1900. 



1341. Kashiwa bark. — The bark of Quercus dentata Thunb. Native of eastern 



Asia. From Japan. 



1342. Konara bark. — The bark of Quercus glandulifera Blume. Native of eastern 



Asia. From Japan. 



