8 NUTRITIVE PLANTS 



vague ; and besides, that it is founded on no experiment, direct or 

 indirect. In this hypothesis too we must imagine a compound alto* 

 gether new, sugar combined with a substance that renders it insolu- 

 ble in cold water ; and sugar has never yet presented us with such 

 a compound, 



Others have supposed, that heat alone is capable of effecting this 

 conversion of fecula into saccharine matter; a fact which, if it were 

 confirmed, might throw fresh light on the saccharine fermentation 

 of Fourcroy. 



Accordingly, starch has been boiled with water four days in suc- 

 cession, till it became extremely fluid. The filtered liquor was 

 evaporated, and the result was a thick mucilage, very bitter, with- 

 out the least taste f sugar. The starch remaining on the filter 

 resisted the action of boiling water, and exhibited a very hard horny 

 matter. . 



It remains to be examined, therefore, whether the sulphuric acid, 

 or the starch itself, be decomposed. 



To judge by the letter from Petersburg, the Russian chemists 

 seem to suppose that a decomposition of the sulphuric acid takes 

 place. 



To account for these phaenomena, we should operate in close 

 vessels. Accordingly, the author we have referred to introduced into 

 a tubulated receiver a hundred grammes of sugar of milk, four of 

 sulphuric acid, and four hundred of water. To the neck of the 

 retort was adapted a tubulated receiver, from which proceeded a 

 sigmoid tube, opening under ajar filled with water. 



After boiling for three hours, no gas had come over, except the 

 air contained in the vessels. A piece of blue paper introduced into 

 the neck of the retort was not reddened. The water that had passed 

 into the receiver was without taste, did not redden litmus paper, 

 had no smell of sulphureous acid, and did not precipitate lime-water, 

 muriat of barytes, or acetat of lead; consequently it contained no 

 sulphureous, sulphuric, acetic, or carbonic acid ; in short, it was 

 nothinabut pure water. 



Bar es-water traversed by the bubbles, extricated during the 

 process, was not rendered turbid in the least, and the gas that had 

 passed into the jars was nothing but the air of the vessels. 



It is evident, that the sulphuric acid had not undergone the 



