ON DEXTRINE AND DIASTASE. 
277 
the temperature raised expecting to see the reactions peculiar to 
diastase, but was somewhat disappointed when the mixture be- 
came gelatinous and exhibited no signs of alteration. At this 
crisis half a grain of diastase was added, dissolved in a very- 
minute portion of water; the mixture in a very short time was 
sufficiently fluid to filter. If the acetic acid solution of gluten 
was prepared correctly, and there is every reason to believe 
that it was, this assertion of Raspail proves incorrect. 
Raspail also asserts, that diastase and sulphuric acid 
possess no power of rupturing the envelopes of fecula, but that it is 
due to the water and temperature. To ascertain how far this 
was correct, 240 grains of fecula about 1000 grains of water, 
and half a grain of diastase, were mixed together, and heat 
gradually applied. At the temperature of 150° Fahr., the 
mixture had a gelatinous consistence owing to the rupture of 
the envelopes, and the liberation of the interior substance. 
Again; the same quantities of fecula and water were mixed to- 
gether without the diastase, and the temperature raised as be- 
fore. At 150° Fahr., the mixture becomes gelatinous as in 
the other case. To this one-third of a grain of diastase mixed 
with half a dram of water was added, and the whole stirred to- 
gether. In a very short time, the mixture lost its jelly cha- 
racter, and was quite fluid. From this it may clearly be in- 
ferred, that water and temperature, as has been said by Raspail, 
are really the agents which rupture the envelopes. It may 
be well to remark, that the jelly of that in which diastase was 
used, was not so thick as the other, which may be traced to the 
immediate action of the diastase on the first portion of broken 
granules. 
Preparation of Dextrine. 
First, by sulphuric acid. 
The proportions recommended by different chemists are 
exceedingly variable, as are the processes. Berzelius directs. 
Fecula 50 parts. 
Acid 20 " 
Water 139 " 
Mix the fecula with one-half of the water, and the acid vvilh 
