LEONARD MUSCATINE 267 



LOOMIS: We grow them happily in 5% artificial seawater. We 

 make up an MBL artificial seawater with deionized water, not dis- 

 tilled. That's the main thing, no copper. In fact, we have nearly a 

 dozen hydroids growing in artificial seawater. Cordylophora grows 

 nicely in 10% MBL water while Chlorohydra grows in 55^ MBL. Of 

 course, that has magnesium in it. 



I would like to make another point. Some day, somebody ought 

 to study how glycerine makes the endothelial cells spit out their 

 contained Chlorella. It would he interesting to study this incredible 

 reaction, as well as to try and reinfect albino green hydra with free 

 Chlorella. I don't think this has ever been done with green hydra, 

 or lichens either. In other words, you can separate; but no one has 

 yet recombined the two symbiotic forms that I know of. 



SLAUTTERBACK: Regarding reinfection, I have taken eggs, 

 which as you know are white, from Chlorohydra and hatched them 

 separately. If the resulting albinos are returned to a culture of green 

 hydra, they remain white for about 2 weeks. 



FULTON: I think some German workers have succeeded in re- 

 infecting white Chlorohydra, but not other species of hydra. Inci- 

 dentally, we found that the antibiotic chloramphenical cures green 

 hydra of the algae in a couple of days, much faster than glycerine. 



MUSCATINE: What concentration was used? 



FULTON: I'm not certain, but I think it was 200 /.ig. per ml. 



AlUSCATINE: I tried various algicides with the anemones, and 

 neither the commercial product Algaedyne, which is a colloidal sil- 

 ver solution, nor a high concentration of Streptomycin, nor starva- 

 tion in darkness succeeded in totally ridding the animal of its algae. 

 When starved in darkness the animal becomes very small but still 

 retains algal cells which can be shown to increase in pigment con- 

 tent. This might be regarded as evidence for heterotrophic activity 

 in these zooxanthellae. 



FULTON: Did you try chloroamphenicol? 



MUSCATINE: No. 



BURNETT: Have you e\'er noticed differences in the distribution 

 of the algae along the column? 



