268 
ORIGINAL COMMUNICATIONS. 
MM. Payen and Persoz, in a letter addressed to the 
Academy, dated 8th of April, that is to say, eight days after 
the letter of M. Guerin, announced the discovery of diastase, 
the active principle of malt, and of the property it possessed 
of breaking or decomposing the globules of fecula, and setting 
at liberty the soluble matter, or dextrine. " This substance," 
(diastase,) they say in their letter, " contains the less azote as it 
approaches a state of purity, and possesses besides the follow- 
ing properties: it is solid, white, insoluble in alcohol, soluble 
in water; its solution is neuter, and its taste marked; it is not 
affected by the subacetateof lead; abandoned to itself for some 
time, it becomes acid; heated to 150° or 160° Fahr., with 
fecula, it possesses the remarkable power of breaking, instant- 
ly, the envelopes, and setting at liberty the dextrine, which 
dissolves easily in water, whilst the teguments, insoluble in 
this liquid, float or precipitate according to the density of the 
liquor. This operation, properly managed, gives pure dex- 
trine, which possesses a great power of rotation, unequalled by 
that obtained by any other process. When diastase is present 
in a solution of dextrine, it always converts the latter sub- 
stances into sugar, provided the temparature is not elevated 
during their contact above 160° or 170° Fahr., because, if 
heated to ebullition, it loses the property of acting on fecula 
and dextrine." 
"Diastase exists in the germinated seeds of barley and 
wheat, and in the germs or eyes of the potatoe, ( Solarium 
tuberosum, J where it is always accompanied by an azotized 
substance which is soluble in water, insoluble in alcohol, capable 
of being coagulated by heat, incapable of acting on fecula, and 
of being precipitated from its solution by subacetate of lead." 
The following is the process for preparing diastase announced 
by Payen and Persoz in the same communication: — One part 
of malt ( d'orge germee ) is reduced to powder, and mixed in 
two and a half parts of distilled water. After macerating for a 
few minutes, the mixture must be thrown on a filter. The 
liquid thus obtained is to be heated to 150° Fahr., when the 
azotized substance is coagulated, and can be separated by filtra- 
