342 JOHN F. FULTON, JR. 



stentorin is not to be considered an important exception to the 

 rule that all protozoan pigments are chlorophyllogenous in 

 nature. 



But how does th(^ chlorophyll of protozoans originate ? 

 Is the animal itself capable of manufacturing chlorophyll, or 

 is it the result of outside infection ? Geddes (18H2) and 

 Jjankester (1882 a, and 1882 h) maintained strenuously that 

 Hydra viridis and Hpongilla fluviatilis were 

 capable of synthesizing their own chlorophyll : ^ that the green 

 deposits found in these animals are chloroplasts belonging to 

 the animal and consequently are not of plant origin. In 

 support of his contention Lankester asserted the absence of 

 nucleus and cellulose wall in the green corpuscles. Though no 

 histological evidence has been adduced to show the presence 

 of a nucleus in these bodies, it seems fair to conclude, since 

 Beyerinck (1890, note 1, p. 784) has succeeded in obtaining 

 cultures of algae from the green corpuscles of Hydra 

 viridis,'- that the chlorophyll of Hydra is algal in nature 

 and due to an infection from the outside. The algae probably 

 represent a phase in the life-history of C'hlorella viridis. 

 A similar condition undoubtedly holds for most of the green 

 protozoa : Famintzin (1889, 1891), Dantec (1892), and Dan- 

 gear d (1900) all report having obtained colonies of algae from 

 the macerated tissues of Stentor, Paramoecium, and Fron- 

 tonia ; Schewiakoff (1891) found that if colourless Frontonia 

 are fed upon macerated green specimens they become infected 

 with green algae which subsequently divide within the cell. 

 Similar results have been reported for Paramoecium (Dantec). 

 Certain contrary evidence is also on record for the Protozoa — 

 the puzzling cases of Yorticella campanula (Engle- 

 mann, 1883), and of Pelomyxa viridis (Bourne, 1891) 



1 For a more complete discussion of this question see Gamble and 

 Keeble (1903). Keeble and Gamble (1907), and Fulton (1921 a). 



" Entz (1881 and 1883) reports similar results, but in his experiments 

 little precaution was taken against infection and consequently the results 

 are to be accepted with caution. Recently Goetch (1921) has succeeded in 

 infecting colorless Hydra with ChloreUa. and in so doing has corroborated in 

 n very substantial way the views of the earlier investigators cited above. 



