METHODS FOR THE STUDY OF FERMENTS 55 



lytic decompositions. The blood plasma is unable, 

 either in the majority of animals or in man, to produce 

 decomposition of albumens, peptones, and poly- 

 peptides, at least not in any degree which can be 

 demonstrated by available methods. The capacity 

 for decomposing fats is also apparently absent in 

 most cases. On the other hand, we often meet with 

 assertions that the blood always has a diastatic action, 

 i.e., the capacity for splitting complicated carbo- 

 hydrates. Under normal conditions the blood plasma 

 does not generally seem to be constructed for the 

 reduction of complicated substances. Only in the 

 l case of guinea-pigs do we find conditions that are 

 undoubtedly exceptional ; here the blood plasma 

 shows other properties, and even under normal con- 

 ditions can partly break down polypeptides which are 

 not in the least acted upon by the blood plasma of 

 other animals. The cause of this peculiar behaviour 

 of the plasma in guinea-pigs cannot yet be explained. 

 That the blood plasma in general is lacking in diges- 

 tive powers must obviously be construed in the sense 

 that, under normal conditions, substances which are 

 out of harmony with the plasma, and require a quick 

 chemical reduction, never have access to the blood. 

 As soon as these observations had been made it 

 become possible to study the question, whether the 

 blood plasma exhibits new properties in cases where 

 substances that are out of harmony with the plasma, 



