S. C, BROOKS 



75 



Dreyer and his coworkers, for example, found that only after a con- 

 siderable period of slow laking, did the course of the hemolysis in- 

 duced by a and /S rays of radium and by ultra-violet radiation follow 

 the course of a monomolecular reaction; this initial lag they call, 

 tentatively, a period of induction. 



Eijkman^ has shown that the shape of the disinfection time curve 

 is peculiar to the particular^culture of bacteria used, and to some 



Fig. 5. The upper curve is the monomolecular reaction isotherm, beside which 

 are plotted experimentally determined points for normal serum hemolysis (Henri, 

 asterisks), the immobilization of Chlamydomonas by 0.009 per cent HCI (Harvey, 

 diagonal crosses), disinfection (Chick, erect crosses), and hemolysis by ultra- 

 violet radiation (original, circles) ; the abscissae were so adjusted in plotting these 

 points as to make their curves coincide with the monomolecular reaction isotherm 

 at 50 per cent. The lower curve represents the course of the same ultra-violet 

 hemolysis, but with the abscissae plotted on a larger scale, and with the addition 

 of 5 points determined during the first part of the process. The ordinates repre- 

 sent degree of completion of the process, and abscissas, time. 



extent characteristic of the species. Both Eijkman and Reichen- 

 bach^ have secured disinfection time curves which, even when determi- 

 nations during the early stages of the process are included, do not 

 diverge very greatly from the exponential or monomolecular type of 

 curve. It is possible to explain such curves either by assuming a 

 monomolecular fundamental reaction and a variation curve of the 

 form y = yo, or by assuming a fundamental reaction proceeding at a 

 uniform rate, and a variation curve of the form 



y = Joe"** (2) 



