COLLEGE OF DENTISTRY 



UNIVERSITY OF CALIFORNIA 



CHAPTER IV 

 VELOCITY OF REACTION. HETEROGENEOUS SYSTEMS 



MOST of the reactions concerned in sero-therapy occur 

 in heterogeneous systems, and may therefore be regarded 

 as analogous to, e.g., the solution of a metal or a carbonate 

 in an acid. To this category belong, for instance, the 

 haemolytic reactions, which possess such great importance 

 for theoretical researches. Madsen and I l have made 

 some experiments on the velocity of haemolysis by sodium 

 hydrate, ammonia, and tetanolysin. The reagents, solu- 

 tions of the haemolytic substances and suspensions of 

 blood-emulsions, were heated to 37 C., mixed and allowed 

 to act upon each other for a certain time, then the mixture 

 cooled down to o C. in order to practically check the re- 

 action, and rapidly centrifugalised. The colour of the 

 solution indicates the degree of haemolysis. 



The velocity of the reaction was calculated under the 

 assumption that the transformed quantity in the unit time 

 is proportional to the number of erythrocytes present. 

 The haemolytic agent was present in such an excess that 

 its quantity was many times greater than that necessary 

 for complete haemolysis. This quantity, being in excess, 

 was therefore regarded as approximately constant during 

 the short time of reaction. Hence the velocity of reaction 

 should be that of monomolecular order in a homogeneous 



1 Festskrift, Copenhagen (1902), No. 3. 

 100 



