74 O^ PEPPER. 



tion of muriatic acid. Let the infufionof pepper be put info 

 a tali glafs veflel, and plunge (lie beak of the retort to the bot- 

 tom ot it, A current of oxyniurialic acid is difengaged from 

 tlie fait, and patfesin bubbles through the inlufion for a conli- 

 derable time. 



When ammonia is added to the infufion thus made while, 

 the original red colour is rellored. The white flakes precipi- 

 tated by oxymuriatic acid gas are infolubie in cold water. 

 Deco4ftion of V. That pepper contains a fpecies oF (larch, I conclude 



pepper affords f^.^^^ ^j^^ following experiment, which I have frequently re- 

 with tattf a pre- . . . -^ 



cip. foluble in peated. When the decoction of pepper is mixed with the in- 



^u ^^^ "°' ^ fiifion of nut-galls, a copious precipitate falls in reddidi brown 

 flakes. If this liquid be heated to the temperature of about 

 120°, the precipitate is re-difiblved, but appears again when 

 the i'olution cools. Now the only fubftance which poifetTes 

 the property of forming with tan, a precipitate nearly infolubie 

 in cold water, but very foluble in hot water, is ftarcb. Tan 

 indeed throws down gluten, but the precipitate is not re-dif- 

 folved in the application of heat. It tlirows down caoutchouc 

 and fome of the gum-refins, but the precipitate is fcanty and 

 probably owing to the extraneous matter. The precipitate, 

 which it forms with gelatine and albumen cannot even by the 

 mottcarelefs obferver, be confounded with the compound of 



Tfcis property is ftarch and tan. But befides this property, which I coiilider as; 



^aradlenftic of ^.^gj-jj^^^fif^jf,^ j|jg ftarch of pepper, agrees with com'.non 

 ftarch in the phenomena which it exhibits with the different 

 chemical reagents. 



Phenomena of As thefe phenomena have not yet been detailed by chemical 



ftarch with re- writers, it may be necctfary to give a fliort Iketch of them in 



•gents. ,, . , ^ ^ 



this place. • 



Starch noteafily *• Starch is one of thofe vegetable bodies that are leaft li- 

 iccompofcd. at>ie ^o decompofition. It conftitutes one of themoft import- 

 ant articles of food, and acts an important part in the produc- 

 tion of fermented liquors. The obvious properties of com- 

 mon fiarch are too well known to require any defcription. 

 Not foluble in 2. Neither alcohol nor elher nor water are capable of dif- 



alcohol, ether, f^i^ing it. The laft liquid when affifted by a boiling heat, 

 or water. ° . . . . . 



readily unites with it, and forms a kind of jelly, which may 



be diffufed through boiling water; but when the mixture is 



allowed to ftand afufficient time, the flarch flowly precipitates 



Forms a jelly ^q i\^q bottom. By drying the compound of flarch and water, 



with hot water ^ ^ u x i • i 



which is little ^ brittle 



changed. 



