24 VELOCITY OF REACTIONS 



we do not know their composition and therefore are> 

 so far, unable to prepare them. These organic 

 products have been characterized above. 



In most cases these substances are very unstable > 

 so that they are rapidly decomposed, especially at 

 higher temperatures. This spontaneous decomposi- 

 tion has often been regarded as characteristic of these 

 substances, but closer investigation indicates, as we 

 will see below, that they behave just in the same 

 manner in their reactions as do well-defined 

 substances known from the general chemistry. 

 Even from inorganic chemistry we know a great 

 number of products which are stable only at low 

 temperatures. 



As regards the progress with time of this decom- 

 position it behaves precisely as an ordinary mono- 

 molecular reaction, as the following figures and 

 diagrams indicate. They give the rate of destruction 

 of tetanolysin at 49-8 C. and of a haemolytic anti- 

 body, found in the serum of a goat after injection of 

 blood-corpuscles from a rabbit, at 51 C. The law 

 of monomolecular reactions states that the curves 

 representing the logarithm of the quantity of the 

 substance in decomposition, e.g. the tetanolysin or 

 the haemolytic antibody, as a function of time, is a 

 straight line (cf. p. 6). 



