134 PHOTOGENIC REACTION IN CYPRIDINA 



hemoglobin), Ba02, Pb02, and other oxidizing agents. Through the 

 kindness of Professor Dubois I have received some material of Pholas 

 dactylus preserved in sugar and I can confirm his results on the effect 

 of KMn04 and other oxidizing agents in producing light with luciferin 

 of Pholas. I have likewise repeated my own experiments with the 

 photophelein of Cypridina using a whole series of oxidizing agents 

 applied in the same way, as with the luciferin of Pholas and, as pre- 

 viously, have failed to obtain any light with this substance.^ The 

 difference in our results is, therefore, not to be referred to a difference 

 in method of experiment but to a difference in the substances them- 

 selves. 



I found also that if one takes a concentrated solution of photogenin 

 filtered through a porcelain or silicious filter candle to remove all 

 granules and cell fragments and adds to it a little saponin powder, or 

 amyl alcohol or NaCl or other inorganic salt crystals or tissue ex- 

 tracts of certain invertebrate non-luminous animals, that light would 

 appear. Because NaCl could not possibly be oxidized by photogenin 

 ( = luciferase) — or any other substance — and because of my inability 

 to make photophelein ( = luciferin) luminesce with oxidizing agents, 

 I regarded the photogenin itself as the source of the light and the 

 oxidizable body. I have compared photogenin to zymase and 

 photophelein to the coenzyme of zymase, believing that we are dealing 

 with a system similar to that of the enzyme-coenzyme system of 

 yeast. Hence the name photophelein or body assisting in the pro- 

 duction of light. 



^ The following oxidizing agents (added ,where possible, in minute crystal or 

 powder form) all gave light with Pholas luciferin, but no light with Cypridina 

 luciferin: KMn04, KsCr^O?, PbO., NasOa, BaOj, Mn02, K3Fe(CN)6, KoSjOg, 

 Na2B408, and H2O2. The following oxidizing agents gave no light with either 

 Pholas luciferin or Cypridina luciferin: K2Cr04, CrOs, KCIO3, KCIO4, FeCU, 

 KNO3, CI or Br water, I in KI, Na hypochlorite, hypobromite, or hypoiodite, 

 colloidal Ag or Pt, benzoyl peroxide, potato or turnip juice, or blood containing 

 hemoglobin or hemocyanin. If H2O2 in addition to the oxidizing agent is added 

 to Cypridina luciferin, no light appears except a faint momentary flash with Na 

 hypochlorite and hypobromite. As this faint flash also appears with thoroughly 

 boiled extracts of Cypridina,- lacking luciferin, it can have no significance. If 

 H2O2 in addition to the oxidizing agent is added to Pholas luciferin the light is in 

 some cases brighter than with H2O2 alone. 



