ENZYMES 449 



was separated by means of a filter press. The clear solution was 

 then mixed with strong alcohol as long as a precipitate was 

 formed, and the latter was collected, washed with alcohol, 

 pressed between a cloth, and dried in vacua over sulphuric acid. 

 Prepared in this way diastase is a white powder, easily soluble 

 in water, and possessing the activity of malt extract. It is, 

 however, far from being a pure substance, as it contains a con- 

 siderable percentage of mineral matter (chiefly phosphate) 

 which is left as ash when the diastase is burnt. 



Calculated on the ash-free substance the results of analysis by 

 two different observers are as follows : 



(Lintner) (Szilagyi) 



Carbon . . . 46-66 .. 46-80 



Hydrogen . . . 7-35 .. 7-44 



Nitrogen . . . 10-42 .. 9-98 



Sulphur . . . 1-12 .. 1-14 



Oxygen . . . 34-45 .. 34-64 



It will be evident on comparison with the analysis on page 426 

 that this is not the composition of an albumin. It should be 

 added that other analyses have led to different proportions of 

 the elements. 



The characteristic property of diastase is its power of con- 

 verting starch under suitable conditions of solution and tem- 

 perature into a mixture of maltose and dextrin : 



5(C 12 H 20 10 ) 20 +80H 2 0=80C 12 H 22 11 +(C 12 H 20 1C ) 20 

 Soluble starch 1 Maltose Stable dextrin 



Diastase, or a substance resembling it in its action on starch, 

 appears to be widely distributed in the vegetable kingdom in 

 leaves and other organs, and it occurs in the grain of all cereals 

 whether raw or germinated. 



Another interesting case is that of the bitter almond. It must 

 have been known as long as the almond itself that this seed when 

 dry or crushed is without peculiar odour. When strongly pressed 

 both sweet and bitter almonds yield a considerable quantity of a 

 bland fatty oil, which may be eaten as food or used for making 

 soap. If the bitter almond is pounded and mixed with water, a 

 characteristic familiar aromatic odour is developed, which is due 



1 This the formula attributed to soluble starch, which is the first, or one of 

 the earliest products, of the degradation of natural starch by acids. 



2 G 



