318 



V, — Treatment with Boiling Water. 



Mix the moist substance, exhausted by ether, alcohol and 

 cold water, in a deep porcelain dish with so much water as to form 

 a very thin pulp, heat under continual stirring to the boiling- 

 point, let boil for an hour, filter, or if necessary, strain through 

 gauze in the manner indicated vinder IV., and wash the remnant 

 with boiling water. 



Determine the weight of the remaining substance in the 

 supposed dry state according to IV., and subtract from the weight 

 of the substance found under IV., the rest representing the weight 

 of the matters dissolved in the boiling water. 



Concentrate the itnited liquids to about 100 grams, and tiy 

 in small portions with the tests indicated under II., B, d; in 

 most cases slight or no reactions will be obtained. 



If no inulin has been obtained under IV., examine on starch, by 

 mixing a portion of the liquid with solution of iodine. A violet or 

 blue colouration indicates starch, which is either a remnant from 

 that obtained by kneading under IV., or it represents, if no starch 

 has been obtained there, the whole amount of starch contained in the 

 vegetable substance. 



If no reaction of starch is obtained, a small amount of intdin 

 might have been present in the vegetable substance, but is now 

 converted into gum by the boiling water. 



Any precipitate, produced by lead-salts, must be examined ac- 

 cording to II., III. and IV. 



VI. — Treatment with Diluted Hydrochloric Acid. 



The substance exhausted by ether, alcohol and water, contains 

 as a rule only constituents of minor interest, and in most cases 

 the analysis may now be considered as finished. Considering, liow- 

 ever, that the object of this work is to investigate every constitu- 

 ent of vegetables, though it be of minor interest, I now resoit to 

 those solving agents which, if employed in the beginning, would 

 have caused alterations and decompositions highly detrimental to 

 the analysis, but which now may be used with comparative im- 

 punity. 



Give the substance left in V., and still moist, into a beaker 

 (weighed befoi-e), make w]) with water to 500 grams, add 20 

 grams pvire hydrochloric acid of 1.12 specific gravity, cover the 

 beaker with a glass-plate and expose to a moderate heat for two 

 days. Filter and wash the substance on a filter with water, until 

 it passes off fi-ee from acid reaction. 



After washing the substance, determine the weight of the dry 

 substance as under IV., subtract from the weight under V. and 

 note down the rest as the weight of the matters dissolved in the 

 acid water. 



