S. C. BROOKS 71 



molecular reaction isotherm. Similar relationships have been reported 

 in the case of hemolysis, which is a process in many ways similar 

 to disinfection •/''~^'* although in this case a so called " induction period," 

 often of considerable length (Dreyer and his coworkers) intervenes 

 before the hemolysis appears to follow the course of a monomolecular 

 reaction. In both hemolysis and disinfection a large number of 

 single living cells are exposed to the action of an agent which ulti- 

 mately induces in the cell some change which we can detect; in one 

 case loss of power to reproduce; in the other, loss of a pigment; in 

 both cases there is great variation in the length of time required to 

 bring about the critical change in different cells. Harvey^^ considers 

 the equation for monomolecular reactions to be applicable to the loss 

 of motility suffered by cells of Chlamydomonas subjected to the 

 action of hydrochloric acid in great dilution; while Darwin and Black- 

 man, according to Arrhenius,^^ saw the same relationship when they 

 allowed various killing agents to act on seeds. These citations, 

 while by no means complete, will suffice to indicate the wide range 

 of phenomena which have been studied from this point of view. 



Some authors, like Dreyer and his coworkers, have not attempted 

 to attribute the apparent analogy of these processes with monomolec- 

 ular reactions to any single relationship, but some other authors 

 have devoted to this phenomenon a great deal of discussion which 

 does not seem to have been based upon a comprehensive knowledge 

 of the subject, for their attempts to explain the analogy will not bear 

 criticism, and none of their criticisms are entirely satisfactory. The 

 difficulty is largely due to failure to see the necessary consequences of 

 uniformity in resistance, or to disregard of the possible influence of 

 progressive changes in the velocity of the fundamental reaction. 



^^ Arrhenius, S., and Madsen, T., Z. physik. Chem., 1903, xliv, 33. 



^^ Henri, V., Compl. rend. Soc. bioL, 1905, Ivii, 37. 



^"^ von Liebermann, L., and von Fenyvessy, B., Z. Immunitdtsforsch., Orig.^ 

 1912, xii, 417. 



^' Salomonsen, C. J., and Dreyer, G., Compt. rend. Acad., 1907, cxliv, 999. 



^^ Dreyer, G., and Hanssen, O., Compt. rend. Acad., 1907, cxlv, 371. 



1^ Harvey, H. W., Ann. Bot., 1909, xxiii, 181. 



^^ Arrhenius, S., Quantitative laws in biological chemistry, London, 1915, 

 interprets in this way the experiments of Darwin, N., and Blackman, A., Rep^ 

 78th Meeting, 1908, Brit. Assn. Adv. Sc, 1909, 902. 



