(32) 



yi6. Toad-flax. Butter-and-eggs. — The stems of Linaria Linaria (L.) Karsf 

 {Scrophulariaceae — Figwort Family). Native of Europe. Used as a flax- 

 substitute. Collected by H. H. Rusby at upper Montclair, New Jersey. 



717. Dish-rag gourd or vegetable sponge. — The fruit of Lujfa Luffa (L.) Lyons 



(Cucurbitaceae — Cucumber Family). Native of the Old-World tropics and 

 widely naturalized in tropical regions. Presented by Lauderback & Sons, 

 of New York City. 



718. The same with the outer layers of the pericarp removed to show the inner 



fibrous framework. Same donor. 



719. Friction brush. — Made from the above and used as a sponge substitute in the 



bath. Same donor. 



720. The same, with a long handle. Same donor. 



721. A fancy box made of the same. Presented by Miss Marie L. Sanial, of New 



York. 



722. Fiber of the fruit of Luffa Luffa (L.) Lyons. From the Philippine Islands. 



Presented by Theodore Miiller. 



Cork and Its Products 



Cork is the peculiar celluar tissue composing the outer 

 layers of the bark of most trees, and serving as a protection 

 for the inner bark, to which belong the tissues so serviceable 

 as textile fibers. The cellulose walls of cork cells are more 

 or less thickly lined with a layer of the peculiar substance 

 suberin, chemically a close relative of fat, and to which the 

 useful properties of cork are chiefly due. In a few trees, 

 the layer of cork tissue is of sufficient thickness and con- 

 tinuity and its properties of lightness, toughness, elasticity, 

 and impermeability are such as to render it of value for the 

 making of bottle-stoppers and for many other purposes. 

 Our present supply of cork comes practically from one 

 species of cork oak (Quercus Suber L. of the Fagaceae, 

 or Beech Family), native of the Mediterranean region 

 and extensively cultivated. The layer of cork, if not arti- 

 ficially removed, would be naturally cast off by the tree 

 after a certain number of years and new layers would be 

 successively produced. For economic use the cork is re- 

 moved in a single sheet or in large pieces and is known as 

 cork-wood. In this condition it contains many fissures and 

 has a very rough external appearance. Preparation con- 

 sists in the removal of such of the outer portions as are 



