Dandeno — Relation of Mass Action to Toxicity. 453 



physiological phenomena. Heald (1. c, p. 136) states : " Now 

 the carbonic acid in aqueous solutions will dissociate to form 

 H ions and C0 3 ions." This is of course quite probably not 

 correct. He states further, p. 137 : " More experiments are 

 necessary to prove conclusively the fact that C0 2 poisoning is 

 due to the effect of the ionic H, and as soon as possible experi- 

 ments with that view will be carried out." From this latter 

 quotation it is quite clear the author had no experimental evi- 

 dence in regard to H 2 C0 3 , yet in the same connection he 

 asserts it as a fact that it dissociates into H ions and C0 3 ions. 

 If the toxic action be due to the H ions, — assuming his pre- 

 diction of the substance to be warranted — it should be as toxic 

 as H 2 S0 4 . But it is only about one-fiftieth as toxic as H 2 S0 4 . 

 This is an illustration of prediction based on the theory of dis- 

 sociation without basis in fact. The author just referred to 

 is not alone in this respect ; and the whole tendency, the whole 

 spirit of the paper, as well as those of some others, seems to 

 assume the theory of electrolytic dissociation is true, and see 

 if physiological action fits in / and where it does not, as in 

 acetic acid, make it fit by assigning function to the whole 

 moleade. 



A cursory glance at the situation might lead one to suppose 

 that the apparent uniformity of toxic action of certain sub- 

 stances, e. g., HCI and H 2 S0 4 , did show a sort of harmony 

 with dissociation. However, a careful examination of this 

 reveals the fact that it is quite to be expected that these sub- 

 stances would act thus, for the simple reason that they are 

 chemically equivalent as a basis of operation. It is not to be 

 wondered at, therefore, that there is such harmony. It could 

 scarcely be otherwise: and so on along the whole line, whether 

 dissociation occurs or not. The only fair conclusion seems to 

 be that the toxic action is a chemical action, because all con- 

 centrations made use of are chemical equivalents. Jones, p. 

 268, states : " It had been thought that the physiological action 

 of any substance was due to its chemical nature." Kahlen- 

 berg and True, p. 85, state : " It has always been taken as axio- 

 matic that the physiological action of any substance is due to 

 its chemical character." Notwithstanding these statements, 

 from the experiments recorded in this paper, it shoidd be still 

 so considered. There seems no doubt whatever that the physi- 

 ological action is due to the chemical properties of the solute. 

 Though the writers just mentioned do not attempt to explain 

 what the nature of the action may be, they lead one to infer 

 that it is due to some subtle action of a physical nature, involv- 

 ing, it may be, a charge of electricity with which the ion is 

 thought to be loaded. 



Dissociation under ordinary circumstances may not take 



