206 



Papers from the Department of Marine Biology. 



for over two days at 20° C. (see table 11) and a shorter time at higher 

 temperatures. As only fresh water and not sea-water will call forth 

 the Ught, and as we know that light-production is connected with the 

 granules of the juice, the process appears similar to the cytolysis of 

 cells — i. e.j to the swelling and solution in fresh water of the granules 

 which the cells contain. By this means something is liberated from 

 the granules of Cavernularia juice which oxidizes with light-production. 

 Table 12 gives the results of adding various other substances, pure or 

 dissolved in sea-water, to the dark Cavernularia juice. 



Table 12. — Effect of substances in calling forth light from non-luminous Cavernularia juice. 



Solution or substance 

 added. 



Character of 

 light. 



Solution or substance 

 added. 



Character of 

 light. 



50 per cent sea-water .... 



66 per cent sea-water .... 



75 per cent sea-water .... 



80 per cent sea-water .... 



90 per cent sea-water .... 



Water 



Sea-water 



Sea-water evaporated to 

 one-half volume 



m cane-sugar 



m/2 cane-sugar 



in/4 cane-sugar 



m/8 cane-sugar 



Chloroform-saturated sea- 

 water 



One-half chloroform-satu- 

 rated sea-water 



One-quarter chloroform- 

 saturated sea-water. . . . 



Chloretone-saturated sea- 

 water 



One-half chloretone-satu- 

 rated sea-water 



One-quarter chloretone- 

 saturated sea-water .... 



Thymol-saturated sea- 

 water 



One-half thymol-saturated 

 sea-water 



One-quarter thymol-satu- 

 rated sea-water 



Benzol 



Ether 



Chloroform 



Chloretone crystals 



Thymol crj^stals 



Chloral-hydrate crystals . 



Saponin powder 



Oleic acid 



Bright light. 

 Fair light. 

 Fainter light. 

 Very faint light. 

 None. 



Bright light. 

 None. 



None. 

 None. 

 Faint light. 

 Fair light. 

 Good light. 



Faint light. 



Very faint light. 



None. 



None. 



None. 



None. 



Fair light. 



Faint light. 



Very faint light. 



Faint light. 



None. 



None. 



Very faint light. 



Faint light. 



Faint light. 



Fair light. 



Faint hght. 



Ortol crystals 



Hydrochinon crystals. . . . 



Resorcin crystals 



Pyrocatechin crystals. . . . 



Pyrogallol crystals 



Ba20'). powder 



Na202 powder 



KMn04 crystals 



K2Cr207 crystals 



FeCls 



FeS04 crystals 



K4Fe(CN)6 



Laonome japonica (an 



annelid) blood 



Dried ox-blood extract in 



sea-water 



Lepas anatifera extract. . . 

 Lepas anatifera extract, 



boiled 



Chiton sp. extract 



Chiton sp. extract boiled 

 Onchidium sp. extract (a 



pulmonale moUusk) .... 

 Onchidium sp. extract, 



boiled 



Dolabelia sp. blood (a nudi- 



branch) 



Dolabelia sp. blood, boiled 

 Sepia esculenta blood .... 

 Sepia escvlenta blood, 



boiled 



Panulirus japonica blood . 

 Panulirus japonica blood, 



boiled 



Cypridina hilgendorfii pho- 



tophelein in sea-water. . 

 Luciola vitticollis photo- 



phelein in sea-water .... 



Faint light. 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



None. 



Faint. 



None. 



None. 



None. 

 None. 



None. 

 None. 

 None. 



None. 

 None. 

 None. 



Faint. 

 None. 

 None. 



None. 



Very faint light 



None. 



Fair light. 



Fair light. 



Note from table 12 that Ught-production is not due to dilution of 

 the salts of sea-water by adding fresh-water, since m cane-sugar does 

 not call forth the Hght. Note also that many cytolytic substances 

 (chloroform, benzol, thymol, etc.) give light, but not the oxidizing 



