220 



Papers from the Department of Marine Biology. 



the tubes. With tohiol, benzol, ether, chloroform, carbon disulphide, 

 carbon tetrachloride, and ethyl biityrate the light was found to disap- 

 pear almost immediately; with tannin, chloral hydrate, vanillin, and 

 sodium glycocholate the light had disappeared in the course of an hour, 

 while saponin, amygdalin, and sodium taurocholate had no effect. It 

 is surprising that saponin has no effect on luminous bacteria when we 

 consider its great cytolytic power on other forms in very small con- 

 centration. 



EFFECT OF POTASSIUM CYANIDE. 



As is the case with other luminous forms, KCN has a surprisingly 

 small effect on the light-production of luminous bacteria as compared 

 with its effect in supressing certain oxidations of many animals. The 

 results are expressed in table 19. 



Table Id.— Effect of potassium cyanide. 



In m/40 KCN the light disappears in 6 minutes, and if the solution 

 is now diluted with sea-water the light returns. The effect is there- 

 fore an inhibition and reversible. 



SUMMARY OF RESULTS FROM LUMINOUS BACTERIA. 



1. Luminous bacteria which have been rapidly dried over calcium 

 chloride in a vacuum will phosphoresce if moistened with oxygen-free 

 water. Drying does not kill all bacteria, but does kill most of them. 

 Hence phosphorescence does not depend on the living cell. 



2. Dried bacteria, if finely ground with sand, will no longer phos- 

 phoresce when moistened. None of the ground bacteria can grow. 

 Phosphorescence does depend upon the integrity of some structure in 

 the cell. 



3. Dried bacteria extracted with ether or toluol will still phosphoresce 

 if moistened and may develop colonies on a suitable culture medium. 

 Consequently neither ether nor toluol destroy the photogen. 



Bacteria in oxygenated sea-water to which ether or toluol is added 

 stop phosphorescing, presumably because the photogenic substance 

 is rapidly oxidized and used up when the bacterial cell is cytolyzed. 



