LIGNUM NEPHRITICUM— SAFFORD, 293 



by many botanists has hitherto been confused with Pterocarpus indi- 

 cus, but which Prain has shown to be quite distinct. Specimens of 

 padouk and of Andaman redwood were obtained from tlie wood col- 

 lection of the United States National Museum. Only one variety of 

 the former was secured, a beautiful red wood with distinct dark an- 

 nular lines of growth. Of the Andaman wood there was an abun- 

 dance of material of several varieties, deep scarlet (from which its 

 American trade name, " vermilion wood," is derived) ; brownish, 

 tending to flesh-color; and with mixed red and brownish streaks. 

 Chips of the deep-red Andaman wood when soaked in ordinary tap 

 water scarcely colored it at all, and showed no fluorescence in ordi- 

 nary sunlight. Chips of both padouk and of pale-colored Andaman 

 wood, on the other hand, yielded a distinctly fluorescent infusion. 



STRUCTURE OF THE WOOD. 



Microscopic sections of the wood of Pterocarpus indieus and P. 

 dalhergioides were studied by Dr. Arno Viehoever, pharmacognosist 

 of the Bureau of Chemistry, and his assistant, Mr. J. F. Clevenger. 

 They found that the resistant resinlike bodies occurring in the large 

 pitted tracheae of Eysenhardtia 'polystachya were absent in both 

 species of Pterocarpus. 



The color of the Pterocarpus wood is caused by certain colored 

 bodies present in variable quantities in all parts of the wood. A 

 study of distinct red masses, occurring chiefly in the medullary ray 

 cells of the sapwood and heartwood (red and light colored streak) 

 of Pterocarpus dalljergioides^ shows a variation not only in the 

 number of these masses but also in their solubility. Solubility tests 

 were carried out with thin sections and observed under the micro- 

 scope with the following reagents : Water, absolute alcohol, acetone, 

 chloroform, ether, petroleum ether, concentrated hydrochloric acid, 

 50 per cent potassium hydroxide and ammonium, at room tempera- 

 ture, giving the following results : In the sapwood the colored bodies, 

 which are relatively scarce, were not dissolved in any of the reagents. 

 In the light-colored streak the colored bodies were soluble in 50 per 

 cent potassium hydroxide and ammonium. In the red wood the 

 colored bodies, being abundant, were readily soluble in absolute 

 alcohol, acetone, 50 per cent potassium hydroxide and ammonium. 



In Pterocarpus indieus yellowish brown bodies, found almost en- 

 tirely in the medullary ray cells, occur somewhat diffused throughout 

 the cells in minute granules and in somewhat larger masses near 

 the end of the cells. These masses are less definitely outlined than 

 the red bodies of Pterocarpus dalbergioides and were soluble in 



