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' 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 Phanseus, as well as the 

 29Q 



