PLANT ANALYSIS AS AN APPLIED SCIENCE 181 



ALCOHOL EXTRACT 



Tannic acids; bitter principles; organic acids; alkaloids; 

 glucosides; glucose; saccharose; coloring- matters; resins. 



WATER EXTRACT 



Mucilaginous and albuminous substances; dextrin and 

 other carbohydrates ; saponin and allied compounds; glucoses; 

 saccharoses; organic and mineral acids. 



DILUTE SODA EXTRACT 



Metarabic acid; albuminous substances; phlobaphenes, 

 etc. 



DILUTE HYDROCHLORIC ACID EXTRACT 



Parabin; oxalate of calcium, etc.; starch. 



DETERMINATION OF LIGNIN AND ALLIED SUBSTANCES AND 

 OF CELLULOSE 



Benzole, chloroform, amyl alcohol, and acetic ether are 

 frequently valuable solvents for certain extractions, although 

 they are not included in the general scheme. 



Dragendorff recommends the maceration to be conducted 

 at the ordinary temperature, but a fixed oil, if present, may 

 be extracted more readily by exhaustion at an elevated tem- 

 perature. Such substances as caoutchouc may be readily 

 extracted by boiling chloroform or bisulphide of carbon. If 

 a known volume of the extract is evaporated, the residue will 

 yield an approximate result of the amount of definite sub- 

 stances obtained in the plant. 



In my own work, I have usually found it convenient to take 

 about twenty grams of the powdered plant and exhaust them 

 in a displacement apparatus. There are some advantages for 

 this method, in a preliminary study of the plant. The time 

 necessary for the exhaustion is very much lessened; from 

 ten to twelve hours at the most is ample time to allow the 

 apparatus to run with each solvent, if the solvents are kept at 



