360 PHYSIOLOGY OF BACTERIA 



reproduction. The independence of the formation of 

 this compound from the concentration of the poison 

 suggests an analogy with the compound observed in 

 serum albumin and yeast. The amount of this com- 

 pound was also independent of the bichloride concentra- 

 tion provided that enough time was allowed for the 

 formation. The minimum time for Micr, pyogenes to 

 lose the power of reproduction under the conditions of 

 this experiment was about one hour. 



This insoluble compound of some part of the pro- 

 toplasm with mercury did not kill the cell, however. 

 When the compound was broken up chemically by 

 the addition of H2S, the mercury was precipitated as 

 HgS, and the protein was set free again, ready to take 

 up its normal function. The bacteria were not really 

 dead after one or two hours' contact with HgCl2, but 

 reproduced after treatment with H2S, if administered 

 within a certain time. Only when the dormant state was 

 quite prolonged, death would set in, and the cells could 

 no longer recover after chemical treatment. 



Thus, the action of HgCU is two-fold. First, there is 

 the ''stunning effect"; a dormant stage is produced; the 

 cell ceases to function. It might be compared with a 

 stone in the cogwheels of the cell machinery. The 

 removal of this ''stone" by chemical means proves 

 that the cell is still alive. At the same time, a slower 

 chemical process takes place which kills the cells. This 

 process is independent of the first. 



The nature of this second process is not clear. It 

 depends upon the concentration of the bichloride. 

 Above 0.1% HgCl2, this relation has been expressed by 

 Gegenbauer in the equation 



killing time X [HgCU]^-^ = 1.5 



