Photobacteria as a reactive in the investigation 

 of the chlorophyll-function. 



Proceedings of the Section of Sciences, Kon. Akademie van Wetenschappen, Amster- 

 dam, Vol. IV, 1901, p. 4549. Verscheen onder den titel Lichtbacterien als reaktief 

 bij het onderzoek der chlorophylfunctie in Verslagen Kon. Akademie van Weten- 

 schappen, Wis-en Natuurk. Afd., Amsterdam, Deel X, 1901, biz. 6974. 



If in a mortar leaves of some neutrally reacting plant, e. g. of white clover are cru- 

 shed, diluted with destilled water, and filtered, a green filtrate is obtained, in which 

 are found that portion of the living protoplasm which is soluble in water, and many 

 chlorophyllgranules which give the filtrate a green colour. 



If this green liquid is mixed with a culture of phosphorescent bacteria in fish- 

 broth with 3 pCt common salt, or with sea-water A ) rendered phosphorescent by a 

 luminousbouillon, and if this mixture is filled into a test-tube or stoppered bottle, the 

 liquid becomes dark as soon as the oxygen has been used by the physiological processes 

 of the phosphorescent bacteria and of the living protoplasm of the clover-leaves in the 

 filtrate. 



If the dark liquid is exposed to light, it is evident that the chlorophyll and the 

 living protoplasm have not become inactive by the said treatment, for, by production 

 of oxygen, they again cause the luminosity of the bacteria. If the plant-juice is fresh 

 and the bottle is placed for a minute or longer in the full sun, then so much oxygen 

 is formed, that the bacteria, transferred to the dark can continue phosphorescing for 

 some minutes. 



This experiment is of an extreme sensibility, for even the lighting of a match 

 is sufficient, after part of a second already, to produce a distinct phosphorescence 

 which, of course, can only be observed when by remaining long enough in the dark, 

 the eye has become sensible to feeble light. 



If the liquid is left to stand for some hours, either as such or after mixing with 

 the phosphorescent culture, the power of decomposing carbonic acid gets quite lost. 

 Evidently the presence of living protoplasm is necessary for it. Concequently, 

 F r i e d e 1's 2 ) experiment, wherein clear, filtered juice of squeezed spinage-leaves, 

 mixed with powdered leaves of the plant, dried at 100 C., causes decomposition of 

 carbonic acid, does not prove, as F r i e d e 1 thinks, that the function of chlorophyll 

 reposes on the action of enzymes, but on the fact, that the portion of the protoplasm 



') By sea-water is meant tap-water with 3 pCt. Cl Na- 



-) J. Friedel, ('Assimilation chlorophyllienne realisee en dehors de 1'organisme 

 vivant. Comptes rendus T. 132, pag. 1138, 6 Mai 1901. 



M. VV. Beijerinck, Verzamelde Geschriften ; Vierde Deel. 



