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THE AMERICAN MUSEUM JOURNAL 



shady place, a reddish color; and thus 

 it will change color in a marvelous way 

 according to the nature of its hack- 

 ground. In the dark, however, or in an 

 opaque vase, it will once more assume 

 its blue color.'"' 



Although he says frankly that he 

 does not understand the phenomena, 

 the learned philosopher, true to his 

 boast that there was no problem in na- 

 ture he could not solve, ends by assert- 

 ing that his experiments have shown 

 him the cause, which he will later pub- 

 lish. This, however, he never did. 



]^ot long after, another such cup was 

 described by a botanist ^ who received it 

 under the name palum indianum. This 

 ingeniously made cup, almost a span in 

 diameter and of uncommon beauty, 

 resulting from the variegated lines 

 adorning it, was accompanied by saw- 

 dust or shavings of the same wood, of a 

 reddish color and of no manifest taste. 

 When water was poured into the cup 

 and the sawdust macerated in it, the 

 water in a short time became tinged 

 with blue and yellow, and when held up 

 against the light displayed beautiful 

 opalescent hues, giving forth reflections 

 of fiery yellow, bright red, glowing pur- 

 ple, and sea green, wonderful to behold. 

 After quoting from the earliest account 

 of lignum neplirHicum, the author 

 notes that the great botanist C^sal- 

 pinius believed the wood to be a species 

 of ash. 



It was not until 1663 that the color 

 phenomena exhibited by the extract of 

 lignum nephriticum were first investi- 

 gated in a truly scientific manner. ^ 

 The account given mentions all phases 

 of the fluorescence, as well as the me- 

 dicinal properties claimed for the in- 

 fusion. The author calls attention to 

 the fact that the wood described by the 



' Bauhin. .Johan. Historio Planfarum, 1650. 



- Hon. Robert Boyle, Experiments and Con- 

 siderations Touching Colours, p. 203, 1664, a 

 Latin translation of which (1667), and also a 

 summary of the results of Boyle's studies in Rich- 

 ard Boulton's edition of Boyle's works (1700), are 

 in the library of the Surgeon General of the Army 

 at Washington. 



learned Jesuit previoush^ cited was 

 called "white Mexican wood," whereas 

 that used in his experiments was of a 

 darker color. He does not find exactly 

 the same variations in color as those 

 named by the Jesuit, but owns that a 

 greater variety appeared when the in- 

 fusion was held in a partly darkened 

 room than when placed in full light. 

 He discovered also that if spirits of 

 vinegar were dropped into the liquid it 

 lost its blue color, but not its yellow, 

 and that the addition of salts of tartar 

 would restore the blue. 



Many writers sought to identify the 

 wood in the centuries following its dis- 

 covery, but the results obtained were 

 very conflicting. Experiments with a 

 piece of wood labeled "cuatl" in the 

 Mexican exhibit at the Paris Exposi- 

 tion led to the belief that the lignum 

 nephriticum of early writers was Eijsen- 

 hardtia amorplioides. It was assumed 

 that l)oth the wood of the white cup 

 which yielded an infusion colorless as 

 spring water, and that of the reddish 

 cup made of palum indianum. were 

 identical with the dark-colored wood 

 used in the scientific experiments just 

 mentioned. This would mean that the 

 great logs described as "larger than 

 very large trees" were those of Eysen- 

 hardtia — an erroneous conclusion, since 

 it is certain that this genus includes 

 only shrubs and very small trees. On 

 the other hand, after an equally ex- 

 haustive research, one author confi- 

 dently asserted^ that the source of the 

 magic wood was not Eysenhardtia at 

 all but a j\Iexican tree belonging to the 

 genus Pterocarpus. If the statement 

 regarding the great size of logs of this 

 wood conflicts with the possibility of its 

 l)eing identified with an Eysenhardtia, 

 so does the description of its small pin- 

 nately compound or rue-like leaves pre- 

 clude the possibility that the plant 

 described could be a Pterocarpus. in 



" See Moller, Hans-.Iacob. Lipnum nephriticum. 

 Berichte der Deutschen Pharmaz. Gesellsch. 23:88- 

 154. Copenhagen. 1913. 



