The Chemistry of Light-Production in Luminous Organisms. 



217 



flask be oxygenated by shaking, before judging as to the emission or 

 absence of light. Observations were made after 10 minutes, 1 hour, 

 and 24 hours. 



LUMINOUS BACTERIA AND BALANCED SOLUTIONS. 



Not only must luminous bacteria be bathed with a certain concen- 

 tration of salts, but any salt of sea-water is not sufficient. It must be 

 a particular salt, although luminous bacteria, as indicated in table 16, 



Table 16. — Effect of various combinations of the salts of sea-water. 



Salt combinations. 



Sea-water 



Artificial sea-water, m/2(100 NaCH-2.2 KCl 

 +2 CaCU-h 10 MgClz) +n/4000 NaOH. . . 



Neutral artificial sea-water 



m/2 NaCl 



m/2 KCl 



m/3 CaClo 



m/S MgCls 



m/2(100 NaCl +2.2 KCl) 



m/2(100 NaCl +2 CaCW 



m/2(100 NaCl +10 MgC^ 



m/2(100 NaCl +2.2 KCl +2 CaCla) 



m/2(100 NaCl +2.2 KCl + 10 MgClo) 



m/2(100 NaCl +2 CaCl>+10 MgClo) 



Light after — - 



10 min. 1 hour. 24 hours 



+ 

 Faint. 



+ 



+ 

 Faint. 

 Faint. 



Faint. 

 Faint. 

 Faint. 

 Faint. 

 Faint. 

 Faint. 



are not so affected by the pure monovalent cations of sea-water as 

 are most cells. 



Note the independence of these bacteria of a balanced medium. 

 The bacteria live and phosphoresce in pure NaCl without the addition 



