The Glow- Worm and Other Beetles 



men, which are at first colourless and pre- 

 sently turn the same colour as the rest. In 

 the Sacred Beetle this initial red is followed 

 by black; the Phanaeus replaces it by the bril- 

 liance of copper and the reflections of the 

 emerald. Ebony, metal, the gem : have they 

 the same origin here then? Evidently. 



The metallic lustre does not call for a 

 change of nature ; a mere nothing is enough 

 to produce it. Silver, when very finely sub- 

 divided by the methods whereof chemistry 

 knows the secret, becomes a dust as poor to 

 look at as soot. When pressed between two 

 hard bodies, this dirty powder, which might 

 be dried mud, a 1 once acquires the metallic 

 sheen and again becomes the silver which 

 we know. A mere molecular contact has 

 wrought the miracle. 



Dissolved in water, the murexide derived 

 from, uric acid is a magnificent crimson. 

 Solidified by crystallization, it rivals in splen- 

 dour the gold-green of the Cantharides. 

 The widely-used fuschine affords a well- 

 known example of like properties. 



Everything, then, appears to show that 

 the same substance, derived from urinary ex- 

 cretions, yields, according to the mode in 

 which its ultimate particles are grouped, the 

 metallic red of the Phanaeus, as well as the 

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