28 VELOCITY OF REACTIONS 



boracic acid to saturation. In this manner these 

 investigators found the regular values reproduced 

 in the diagram. In an analogous manner they 

 obtained regular results by adding powder of 

 magnesium oxide. 



This example is very characteristic and indicates 

 the special difficulties in experiments with organic 

 matter. The molecular weight of the organic 

 preparations is in general very high, so that there 

 are relatively few molecules present in the solutions 

 used. These preparations react with other substances 

 present, such as salts, and especially with acids and 

 bases. Even when the concentration of these sub- 

 stances is very low, the number of their molecules 

 is of the same order of magnitude as that of the 

 organic molecules, so that these may for a great 

 part be transformed and give quite unexpected 

 reactions. Very often the preparations are taken 

 from a bouillon-culture, which has an alkaline re- 

 action. In this case the rate of decomposition 

 generally increases with the alkalinity. Therefore 

 in such a case, which was investigated by Madsen, 

 namely, that of the spontaneous decomposition of 

 a specimen of vibriolysin, the constant of reaction 

 was double as great for the original solution as for 

 this solution diluted to half its strength. The alkali 

 present had been diluted at the same time as the 

 solution of the lysin. 



A very interesting case of this kind has been 

 observed by Miss Chick and Dr. Martin, when 

 they examined the coagulation of egg-white (in acid 



