PHOSPHORIC INSECTS. 143 



This experiment was witnessed by many emi- 

 nent savants, among whom were MM. Berard, 

 Dujes, Dubreuil, Balard, and Moquin-Tandon. 



M. Schnetzler, of Vevey (Switzerland), made 

 some experiments upon Lampyris noctiluca in 

 1854. He attributes the light of these insects to 

 the combustion of phosphorus, which he thinks 

 he has found in the greasy tissue which constitutes 

 the luminous organ of the insect.* Phosphorus 

 probably exists in the luminous tissue, but only 

 in the state of phosphates. By heating this tissue 

 with nitric acid until complete dissolution was 

 obtained with destruction of the organic matter, 

 M. Schnetzler procured a solution showing those 

 chemical reactions which characterize phosphates. 

 But that does not prove that phosphorus in a free 

 state exists in this tissue. 



An English chemist, Mr. Thornton Herapath, 

 asserts, on the other hand, that the most delicate 

 analysis did not show the slightest quantity of 

 phosphorus (as phosphate) in the bodies of those 

 insects. 



Here, then, we have one observer inferring the 

 existence of free phosphorus after finding phos- 

 phates, and another denying the existence of free 

 phosphorus after seeking for phosphates only. 

 Mr. Herapath thinks, in his turn, that the light 

 of the glowworm is due to a compound of hydro- 



* ' Archives des Sciences Physiques de Geneve,' Nov. 1855. 



