94 Dr. F. W. Gamble and Mr. F. Keeble. [Apr. 24. 



We have demonstrated the dependence of starch formation in the 

 green cells on the presence of light, by maintaining animals in darkness 

 till all reserve-starch has disappeared and then exposing them to light. 

 Starch makes its appearance in the green cells after less than ten minutes 

 exposure to bright sunlight. 



By the use of monochromatic screens, we show that the rays which 

 are most active are as in plant chloroplasts those between B and C 

 (Fraunhofer lines); that no assimilation (as measured by reserve 

 starch) takes place in the green ; that some occurs in the blue. The 

 spectrum of the alcoholic extract of chlorophyll of Coiwoluta examined 

 by the hand spectroscope shows the chief absorption band of chlorophyll 

 (between B and C) and strong absorption of the blue end. 



II. Development of the Green Cells. 



A. General. Direct proof that the green or yellow cells of protozoa, 

 Coelenterates, Turbellaria and other animals are due to an infection 

 from without has been obtained only in the cases of sea anemones 

 (Brandt 4 ), Hydra viridis and Stentor (Beyerinck 5 and Famintzin 6 ). The 

 pure cultures, in the latter cases, have been identified with the green 

 alga, Chlorella vulgaris. A similar origin by infection is assumed for 

 the green cells of other animals, and the relation is generally regarded 

 in all cases as a symbiosis. 



B. Previous Observations. With respect to Convoluia, Haberlandt 

 failed to cultivate the green cells. Observing their remarkable 

 histological features (absence of cellulose wall, c.), he put forward 

 the hypothesis that the green cells are now parts of the animal animal 

 cells to which a leucoplast is transmitted from the egg. 



Georgevitch" hatched out Convoluta, showed that it develops as a 

 colourless larva, and claims that such a colourless larva, if kept in 

 sterilised water, fails to develop green cells and dies within two days. 

 He concluded that the green cells gain access to the animal from the 

 sea-water. 



C. Experiments of tlie AutJwrs. Our experiments lead us to the 

 following conclusions : 



A leucoplast cannot be detected in the egg. 



Convoluta, hatched in sterilised water, may live for two weeks 

 therein. 



The first indication of the future green cell is colourless and not 

 green. Infection, if it occur, is by a colourless cell. 



The precautions to insure sterile conditions taken by George- 

 vitch and by ourselves in our earlier experiments are useless. 

 In these experiments the egg-capsule was placed in sterilised 

 water. We find, however, that the egg-capsule bears a rich 

 and varied collection of green, pale green and colourless cell- 

 colonies. 



