228 



Papers from the Department of Marine Biology. 



Among the substances of class (1) may be mentioned MnO 2 , mixtures 

 of Mn(OH) 2 and Mn(OH) 3 , H 2 Mn0 3 , Fe 2 Fe(CN) 6 , and Ag 2 O. All give 

 light. I have observed no light with boneblack, Pb0 2 , Ag 2 Cr0 4 , 

 PbCrO 4 , BaCr0 4 , Ag 4 Fe(CN) 6 , Pb 2 Fe(CN) 6 , Zn 2 Fe(CN) 6 , Cu 2 Fe(CN) 6 , 

 HgO, Cu(OH) 2 , Cu 2 O, CuO, FeO, iron filings, Hg 2 Cl 2 , Cr 2 3 , Cr(OH) 3 , 

 Fe(OH) 3 , Pt black, and silica. 



Among the group (2), a silver sol protected by protein so as to be 

 fairly concentrated gave a good light. Concentrated Pt sol and Au 

 sol also gave light. Colloidal Fe(OH) 3 and copper oxide gave nega- 

 tive results. 



TABLE 22. 



The following salts gave the best light in the concentrations indi- 

 cated: m/10 to m/20 IQFeCCNk m/100 K 2 Cr 2 O 7 , m/50 K 2 CrO 4 (the 

 light appears only after a long time), m/100 KMn0 4 , m/100 Cr0 3 , 

 m/10 FeCl 3 . The following gave no light: K 2 S 2 8 (m/10 to m/320), 

 KC10 3 (m/10), K 3 Fe(CN) 6 (m/10 to m/1000) MnCl 2 (m/10), AgN0 3 

 (2 per cent), CuS0 4 (m/10), and bromine water. The mechanism of 

 the action of these diverse substances will be considered in a subse- 

 quent paper. 



Peroxide. Only H 2 O 2 will give light with pyrogallol and an oxidase. 

 Na 2 2 , benzoyl hydrogen peroxide, quinone, Ba0 2 , or ozonized turpen- 

 tine do not, although they give a strong guaiac reaction with the per- 

 oxidase of turnip-juice. We must also add H 2 O 2 to potato-juice, which 

 already contains an organic peroxide whose oxygen may be transferred 

 to guaiac. It is no doubt in too small a concentration to give light 

 with pyrogallol. 



Oxidizable substance. Many of the amino- and hydroxy-phenols are 

 rapidly oxidized by potato-juice + H 2 2 , but pyrogallol was the only 

 one which gave light. The following were tried and all gave colored 

 oxidation products: phenol, tricresol, pyrocatechin, resorcin, hydro- 

 chinon,orcinol, o-napthol, ortol, anilin, o and p toluidin, a-napthylamin, 

 guaiacol, para-phenylen diamine, amidol, and pyramidon. Phloro- 

 glucin, B-napthol, and 5-napthylamin were not oxidized. 



Among the glucosides, vanillin, amygdalin, phloridizin, salicin, sapo- 

 nin, and esculin gave no light with potato-juice, either at 20 or 60 C. 



