62 BACTERIOLOGY. 



however, this purple pigment is like chlorophyl 

 or leaf -green, and must be regarded as a feebly- 

 acting chromophyl which effects possible as- 

 similation of carbon dioxide. 



A specially striking adaptation to life in the 

 presence of air is seen in the phenomenon of 

 phosphorescence or luminosity. This phenom- 

 enon, which has been investigated by Pfliiger, 1 

 Fischer 2 and Beyerinck, 3 is to be noticed in 

 decomposing meat and fish and particularly in 

 the phosphorescence of sea-water. As has 

 been shown by Beyerinck and my assistant 

 Weleminsky, it is a vital phenomenon which 

 passes away with death. During life it is de- 

 pendent upon an abundant supply of oxygen. 

 If the oxygen is replaced by another gas, the 

 luminosity disappears, only to appear again 

 when oxygen is readmitted. Those luminous 

 bacteria which are facultative anaerobes do not 

 show phosphorescence in the anaerobiotic con- 

 dition, but only upon the entrance of oxygen. 

 The power of luminosity may be lost in 

 cultures. 



The remarkable substances known as 

 bacterial pigments, among which we find almost 

 all colors represented, belong to quite diverse 



1 Pfluger's Arch. Bd. X., 1874, and Bd. XL, 1875. 



2 Die Bakterien des Meeres nach den Untersuchungen der Plank- 

 ton-Expedition, 1894. 



3 Arch. Neerd. XXIIL, 1889. 



