iS93. EXPERIMENTS ON LIVING CELLS. 431 



dextrin, albumen, g^lue, were also successfully employed as neutrali- 

 sing agents ; while sugar and salt, which dissolved in the water, were 

 almost wholly ineffective. 



Results were for a time much confused by the persistence of 

 after-effects in the vessels. The glasses in which coins had been 

 immersed retained, to some degree, oligodynamic power, even after 

 careful cleansing, and the effect continued, all unknown to the 

 experimenters, during three or four subsequent cultures. 



Nageli had now arrived at what seemed to be a deadlock ; that 

 almost insoluble substances should exert so fatal a power, and that 

 quite insoluble substances should be effective in counteracting it, was 

 very mysterious. 



Would electricity, or some such imponderable agent, he asked, 

 account for the facts ? And so there were started new experiments 

 to put this theory to the test. 



The first bore upon Temperature ; but here again he was 

 baffled, as neither excessive heat nor sudden change accounted for 

 the hidden force. 



The effect of Light was questioned, and that also gave no response. 



There remained Electricity. Had it been generated in the water 

 by the metals employed, and did Spirogyra cells act as an electroscope, 

 exceeding anything hitherto known in sensitiveness ? This theory 

 also was found untenable. Vessels of water were separately charged 

 with positive and negative electricity, and the plants were put in. 

 They remained unaffected, and equally so when a strong induction 

 current of electricity was passed through a tube in which filaments 

 had been placed. The plants were further exposed to the direct action 

 of electricit}' from a battery ; this caused the cells to swell, and 

 induced other changes, but it in nowise resembled the action of 

 oligodynamics. 



The only conclusion left was that here was a new power not to 

 be accounted for by any present theories ; either a new agent was at 

 work, or the old agents had developed new properties. 



The problem was attacked again, to see if the metals above- 

 mentioned acted in solution or in mass. Gold and platinum are 

 quite insoluble ; they had already been tested, but the gold coins used 

 were alloyed with copper. Pure gold was prepared from gold 

 chloride, and the platinum was treated with hydrochloric acid ; they 

 were then found to be harmless, and also it was now proved that 

 washing with acid would neutralise oligodynamic glasses. Thus it 

 was, in all probability, some barely soluble substance, such as copper, 

 that had to be dealt with. 



Oligodynamic water was analysed, and was found to contain 

 lead, zinc, copper, and iron. Some copper coins were left for a 

 stated time in water till it became strongly oligodynamic. On 

 analysis, the solution }ielded one volume of copper to seventy-seven 

 million volumes of water. 



