276 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1915. 



is Yellowish or Reddish, as the Tincture is weaker or stronger. And since he 

 tells ns, that the Tincture will afford all sorts of Colours, and resume a ceru- 

 leous Colour in the Dark, I could wish to know how he was convinced of the 

 latter; and as for the Former, I have tryed that it would not at all answer. 

 Tho' this I must needs own, that having held a Tincture of Lignum Ncphri- 

 ticum in the Rays of the Sun, in a darken'd Room, partly in and partly out, and 

 also, wholly out of the Beams but partly near them, it afforded a much greater 

 Variety of Colours than in a ligliten'd Room. 



In this Experiment it is not a little to be admir'd, that the Blew Colour 

 should be so easily destroyed, whereas the Yellow Coloiir is so durable ; and 

 further, that Acid Salts should destroy it and a Sulphureous one restore it 



CONFUSION OF BOTANICAL NAMES. 



The source of lignum nephriticum remained unknown for cen- 

 turies. Monardes (1565) knew nothing of its origin except that it 

 came to Spain from Mexico. Csesalpinius (1583) and Caspar 

 Bauhin (1623), as we have seen, supposed it to be a species of Frax- 

 irms. Terrentius, in Recchi's epitome, of Hernandez (1651), referred 

 it to the legimiinosse but did not attempt to identify it. Johan 

 Boeclerus (1745), believing it to be a laburnum, called it Cytissus 

 mexicanus. Linnseus, in his Materia Medica (1749) added to the 

 confusion by referring it to Moringa pterygospernha., an East Indian 

 tree; while Guibourt, in his Histoire abregee des drogues (1820), 

 identified it with the West Indian cats-claw {Mimosa unguis- 

 cati L.). 



The first to indicate its true botanical classification was Dr. 

 Leonardo Oliva, professor of pharmacology in the University of 

 Guadalajara, in his Lecciones de Farmacologia, vol. 2, p. 429, 1854, 

 who identified it with Varennea polystachya DC. (Vlhorquia poly- 

 stachya Ortega; Eysenhardtia amorphoides H. B. K.). Subsequent 

 authorities, however, did not accept his identification. Dr. Fernando 

 Altamirano (1878), while recognizing the identity of the coatli of 

 Hernandez with the tree called by the modern Mexicans palo dulce 

 and referring it to Viborquia polystachya Ortega, was not aware 

 that the latter was the same as Eysenhardtia amorphoides H. B. K., 

 and he followed Alfonso Herrero in referring lignum nephriticum 

 to Guilandina moringa^ a mistake which may be traced at once to 

 Linnaeus. In describing the uses of coatli wood b}'^ the modern 

 Mexicans, he states that the country people make drinking troughs 

 of it for their fowls to guard against certain epidemics to which the 

 latter are subject ; or, if the vessel from which they drink is of some 

 other substance, they put a piece of wood in the water and allow 

 it to remain there. The water assumes a blue color, he says; but 

 Mariano Barcena, who experimented with it, observed that the blue 

 color was the result of the refraction of light, and the water, instead 



