VELOCITY OF REACTION. HOMOGENEOUS SYSTEMS 93 



The two processes are undoubtedly of a very different 

 nature. Here it is supposed that the precipitins, like ren- 

 net, obey the law that the product of time and reacting mass 

 was constant. Then if, for instance, o.i c.c. of 10 n. H 2 SO 4 

 acting upon 8 c.c. of egg-albumen solution coagulates it 

 in 90 minutes at 35.8, we expect that 0.3 c.c. of this acid 

 will give coagulation in 30 minutes. Now this quantity 

 cogulates the egg-white solution in 90 minutes at 19.9. 

 Therefore we say that the velocity of reaction is three 

 times greater at 35.8 C. than at 19.9 C. In this manner 

 the variation of the velocity of reaction with temperature 

 may be calculated and from that the value of p. In an 

 analogous manner we observe with the precipitin the 

 quantity necessary to give a unit of precipitate in a given 

 time, and from this we calculate the different times in 

 which the same quantity of precipitin will give the same 

 degree of precipitation at the different temperatures. 

 Probably a closer investigation will show that the premises 

 of our calculation are fulfilled. 



An interesting instance of a bimolecular reaction has 

 been found by Madsen and Walbum 1 in the interaction 

 between tetanolysin and pepton. A solution of 2 g. of 

 Witte's pepton in 100 c.c. water and another of 2 per cent 

 tetanolysin in physiological salt-solution were prepared. 

 Mixtures of 4 c.c. of the solution of lysin heated to 36.iC. 

 with o. 1 5, 0.20, and 0.25 respectively of the solution of pepton 

 (of 36.1) and so much physiological salt-solution of 36.1, 

 that the whole equalled 8 c.c. were placed in a water-bath 

 at this temperature and the haemolytic power determined 



1 Madsen and Walbum : CentralbLf. Bakteriologie, 40. 409 (1906). . 



