8O FORMATION OF DEFENSIVE FERMENTS 



Finally, the behaviour of fatty products was tested. 

 In this case difficulties of method were encountered 

 at first. The experiment made to ascertain the decom- 

 position of fat in the blood, by simple titration of 

 the acids produced, failed entirely. The question, 

 whether, after the introduction of fats that are out 

 of harmony with the body and the plasma, an increase 

 follows of the amount of lipase in the plasma, could 

 only be attacked after Michaelis and Rona had 

 selected the alteration of surface-tension during dis- 

 sociation as the basis of a method for the study of 

 the decomposition of fats. The fats belong to a 

 group of substances that are strongly surface-active, 

 while the products of disintegration produced by their 

 decomposition, such as alcohol and fatty acids, 

 possess no marked influence over surface-tension. . If 

 plasma of a normal animal be mixed with any kind 

 of fat, such as tributyrin, and the mixture be allowed 

 to flow from a capillary tube, a certain number of 

 drops escape in a given time. But if any fat gets 

 into the animal's circulation by whatever means, then 

 the number of drops escaping through the capillary 

 tube decreases. 



As far as we can judge from the experience gained 

 up to the present, it seems that the conditions met 

 with in fats are much more complicated than in the 

 case of proteins and polysaccharicles. This experi- 

 ence tells us that while, under normal conditions, 



