270 
ORIGINAL COMMUNICATIONS. 
which holds the carbonic acid, and which gives to the froth 
its persistence. 
The teguments contain carbonate and phosphate of lime 
and silica. 
The jelly ( empois of the French ) yielded when fecula is 
boiled in water, is accounted for by the swelling of the ami- 
done when in contact with the water, after the rupture of the 
envelopes. When diastase is added to this gelatinous mass, it 
has the singular property of destroying its spongy organic 
character, and of rendering it perfectly soluble by converting 
it into dextrine, and sugar. 
In conclusion, MM. Payen and Persoz remark, — 
1st. That the fecula of the grains and potatoes are formed of 
amidone and teguments. 
2d. That the teguments vary in different feculse, by the 
presence and proportion of an acrid, disagreeable, tenacious 
substance, which communicates to them their special taste. 
3d. That in the action of water, lime water, iodine, baryta, 
and diastase, these substances pass through the envelope. 
4th. That amidone is chemically identical in different fecu- 
lse, but varies in its volume and cohesion. 
5th. That it is insoluble in the cold, but allows water to 
penetrate between its particles, and swell them by degrees. 
6th. That it is spongy in its texture, and when considerably 
broken up by strong ebullition, in 100 times its weight of 
water, it appears to be really dissolved, and passes the filter. 
7th. That the previous observations explain the formation 
of jelly, and its different characters when obtained from differ- 
ent feculae. 
8th. That the teguments, entirely deprived of amidone, do 
not yield a blue color with iodine. 
9th. That amidone alone, in fecula, produces alternately, the 
phenomena of coloration and decoloration, of opacity and dia- 
phaneity, by iodine, alcohol and water. 
10th. That amidone only of fecula, is transformed into sugar, 
and gum, by the influence of diastase, water, and temperature, 
