462 On Vegetable Ivory. [Sess. 



of the various layers of tissue in the testa will be best under- 

 stood by referring to the accompanying illustration (fig. 1). 

 Prominent among these tissues is the layer of columnar cells. 

 This .form shows polygonal cells, with much lignified walls, 

 numerous radiating pores, and the central canal occupied by 

 small hexagonal cones (fig. 2). I have not been able to find 

 a description of these curious cones in any work on stru.ctural 

 botany. They fit into an expansion of the canal at the outer 

 end of the columnar cell, and if the testa is macerated in 

 strong potash, the cones drop out easily on the application of 

 pressure. By grinding a very thin section of the testa a ver- 

 tical view is obtained, and this shows the radiating pores and 

 polygonal cell- walls (fig. 3). Preparations from the hilum 

 show strongly developed scleroid. When the endosperm 

 solidifies it contracts a little, and becomes detached from 

 the testa. The rupture takes place in the middle of the 

 fibrous layer, and a complete coat of the latter adheres to the 

 endosperm. A network of veins may readily be observed 

 traversing this tissue. It consists either of fibro- vascular 

 bundles, or of the grooves formerly occupied by them. In 

 the latter case, the fibro-vascular bundles have adhered to 

 the testa. 



Seeds of Phytelephas macrocarpa are imported in large 

 quantities by London merchants under the name of " Corrozo 

 nuts," a Central American name, and numbers of them are 

 forwarded to the button-makers of Birmingham. The ingenious 

 mechanics of that busy town convert the nuts into buttons, 

 trinkets, drawer-knobs, umbrella-handles, dominoes, chess-men, 

 and other articles where a hard white material, susceptible of 

 taking on a high polish, can be used to advantage. They 

 were first imported to this country in 1826. The present 

 market price varies from £15 to £25 per ton, according to 

 quality. Another palm-nut, from Attalea funifera, is known 

 among turners as " Coquilla shell," and used by them for 

 similar purposes ; but the colour is light mottled-brown in- 

 stead of white. 



A recent number of the ' English Mechanic ' contains an 

 article describing a process now being carried on in Paris for 

 the production of artificial ivory. It is obtained by mixing 

 phosphate of lime, carbonate of lime, magnesia, alumina, 



