146 Dr. W. Roberts. Estimation of the Amylolytic [May 5, 



agents bear to their organic substratum is analogous, or at least com- 

 parable, to the relation subsisting between a mass of protoplasm and 

 the vital endowments with which it stands possessed. 



The activity of preparations of the soluble ferments can only be 

 gauged by their capacity for work. But inasmuch as there is in them 

 no power of growth and multiplication, the amount of energy with 

 which they are endowed is strictly limited, so that when the capacity 

 for work existing in a given liquid or solid preparation of one of these 

 ferments has been ascertained, and has been put into due expression, 

 the amount of energy in a certain quantity of: the preparation can be 

 counted in grams or cubic centimetres like that of any other chemical 

 agent. 



The term ferment has, up to this time, been applied in common to 

 two groups of agents, which, although nearly allied both in their 

 origin and in their mode of action, belong to essentially distinct 

 categories. The organised or formed ferments, of which yeast is 

 the type, are independent organisms with powers of growth and 

 reproduction ; and the transformations which constitute their special 

 characteristics as ferments are inseparably associated with the nutri- 

 tive operations of these organisms. The ferment-power cannot be 

 separated from the ferment-organism by any method of filtration, nor 

 by any solvent. The soluble ferments, on the other hand, pass freely 

 into solution in water — their action is dissociated from the life of the 

 gland-cells which produced them — and they are wholly devoid of the 

 power of growth and reproduction. 



Kiihne has proposed to distinguish the group of soluble ferments by 

 the name of " enzyms." I would suggest the desirability of adopting 

 this term into English, with a slight change of orthography, as 

 ''enzymes," and also of coining from this root the cognate words 

 which are requisite for clear and concise description. The action of 

 an enzyme may be designated enzymosis, and the nature of the action 

 may be spoken of as enzymic. In the present paper I shall venture to 

 employ these terms in the sense here indicated. 



The pancreas is known to be the source of two ferments or enzymes, 

 of capital importance in the digestion of food, namely, an amylolytic 

 enzyme, pancreatic diastase, and a proteolytic enzyme, trypsin. It is 

 also known that the pancreas takes an important share in the diges- 

 tion of fats, but it is doubtful whether its power in this respect is due 

 to an enzyme or to an agency of a different character. The present 

 paper concerns itself solely with the amylolytic and the proteolytic 

 functions of the pancreas. 



Estimation of the Amylolytic Activity of Pancreatic Extracts — 

 Diastasimetry . 



Probably the most accurate mode of estimating the activity of a 



