MECHANISM OF DEATH 341 



course of the reaction. Inasmuch as the constant K obviously 

 changes with a change in the salt concentration, it must be assumed 

 that the reacting substances of the bacterial cell (whether those 

 cells are dead or alive) must always be present in excess if anything 

 approaching the monomolecular curve is to be attained." 



The author holds the opposite view. The monomolec- 

 ular type of reaction is based on the decreasing numbers 

 of living cells. A decrease of the concentration of 

 poison has never been observed, nor does it enter the 

 mathematical equation at all. 



The assumption that the reagent whose decrease was 

 observed, i.e., the Hving cells, is, in reahty, constant, and 

 that the other reagent about whose concentration noth- 

 ing is known, is the decreasing compound, seems unjusti- 

 fied. The argument of Falk and Winslow that the rate 

 of reaction changes with the concentration of poison, is no 

 proof for their contention. 



The change in the concentration of poison molecules can be but 

 slight. To prove this, let us consider the action of 0.01 % of HgCl2 

 upon a suspension of Bad. coli with 1,000,000 cells per c.c. The 

 amount of HgCl2 per 100 c.c. is 10 mg; the weight of the bacteria 

 (Table 132, p. 397) in 100 c.c. is 100 X 10^ X 8 X IQT^^ = 0.08 mg. 

 Of this weight, 70% is moisture, the dry weight being only 0.024 

 mg. The ratio of HgCl2 to bacteria bodies is 10:0.024. In 

 order to compare molecules with molecules, these two weights 

 must be divided by their molecular weight. That of HgCU is 271.52; 

 that of the bacteria cannot be stated; the weight given includes cell 

 wall and cell contents; only parts of the latter will react with the 

 bichloride. But assuming the entire weight to consist of protoplasm 

 with a molecular weight of 10,000, we find the ratio of the numbers 

 of acting molecules to be 0.037:0.000,0024, or 15,000 molecules of 

 HgCh for each molecule of bacterial protoplasm. Even if 4 or 10 or 

 100 of these 15,000 poison molecules should react with one of proto- 

 plasm, their concentration would remain practically unchanged. 



