CULTIVATING ALGAE FOE SCIENTIFIC KESEAKCH^ 



By Florence E. Meiee 

 Division of Radiation and Organisms, Smithsonian Institution 



[With 3 plates] 



Carl von Nageli, the old master of botany, once planted some 

 slimy green spirogyra plants in three aqitaria. Surprisingly, the 

 plants in the aquarium first planted died immediately, those in the 

 second aquarium lived longer, while those in the third aquarium 

 flourished until the tank was a mass of green slime. Time and again 

 the plants in the aquarium first planted died while others lived. 

 What 'was the answer to this puzzling riddle ? Could it be the fault 

 of the algae plants, all of which were similar when placed in the 

 three tanks? Or was it due to the water, all of which came from 

 the same supply and was supposedly pure ? Von Nageli, after ponder- 

 ing for some time, found the answer. The water in the three aquaria 

 was not the same. True, it all came from the same well, but the 

 water for the first aquarium had rested for some time in lead pipes. 

 It had also come in contact with the brass cock, and had had time 

 to dissolve some metal. The water for the second aquarium con- 

 tained the residue of that water which had been enclosed in the pipe. 

 But the water for the third aquarium came streaming directly from 

 the well and was in contact with the lead pipes and brass cock for 

 such a short time that it dissolved practically no metal. To prove his 

 theory, Von Nageli dropped a copper twopenny piece in a liter glass 

 container of water that was pure and free from any trace of metal. 

 He let it stand for four days, then filled the aquarium with healthy 

 green filaments of spirogyra. Within one minute all the algae had 

 died. 



In fact, copper has so toxic an effect on algae that it is a very 

 simple matter to remove all the green slime from a large pond. 

 One needs only to attach to a rowboat a bag of copper sulphate and 

 then drag it through the pond several times. 



^ This paper was written while the author was engaged in research as a National Re- 

 search Fellow in the biological sciences at the Smithsonian Institution. 



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