556 History of Luminescence 



During the nineteenth century, Pyrophorus continued to be de- 

 scribed by many travelers to the West Indies and South America 

 and by scientists interested in luminescence. Karl Iliger's mono- 

 graph on luminous elaterid beetles appeared in 1807, with descrip- 

 tions of sixteenth luminous species of the genus, Elater. Macartney 

 (1810) told of finding a yellow substance composed of globules in 

 the light organs. His drawing of the insect is reproduced in figure 5. 



The first study of the spectrum of the light of Pyrophorus was 

 made by the great Louis Pasteur (1864) , who noted that it was 

 continuous, without dark or light bands. However, it was not until 

 the monographs of C. Heinemann (1872, 1886) and R. Dubois 

 (1886) that the morphology, histology,^'' physiology, and chemistry 

 of Pyrophorus became well known, while the physical studies of 

 Dubois and of Langley and Very (1890) hailed the animal as pro- 

 ducing " the cheapest form of light." Possibly the insects's greatest 

 claim to fame stems from the biochemical experiment of Dubois in 

 1885, by which he established the existence of a thermostabile sub- 

 stance and a thermolabile enzyme, luciferin and luciferase, both 

 necessary for light production. 



Myriapoda 



Probably the first record of luminous centipedes or scolopendrae 

 is that of Oviedo (1520), already described in Chapter HL He 

 found them on the island of Santo Domingo in the West Indies. 

 In addition, early naturalists of the sixteenth century, like Muffet 

 (1634, 1638) , named several persons who saw them in Europe. At 

 that time they were called Julus, a name now reserved for non- 

 luminous species with two pairs of legs on each segment of the body, 

 of the order Diplopoda. 



During the seventeenth century, luminous centipedes were re- 

 corded by Christian Frederick Carman and by John Ray (1628- 

 1705). In his posthumous work, Historia Insectorum (1710:45), 

 Ray stated that " one evening after rain I found a small Scolopendra 

 of this Sort [with 48 pairs of legs] shining like a glow-worm; 'twas 

 covered with a slimy Matter, which being wiped away it ceased not 

 to shine." 



Carman (1670) wrote that his Scolopendra, commonly known as 

 " Nassel," " shines so in the dark that one is reminded of particles 

 of glowing coal " but " after death not the smallest spark remains." 

 Carman went on to quote Kircher and Bartholin as evidence of the 



^^ In a short note, Kolliker (1859), after dissecting dried and moistened specimens 

 of " Elater," called attention to the essential similarily in structure of its light organ 

 with that of the glowworm, which he had studied in 1857. 



