eg THE JOURNAL. OF PHARMACOLOGY. 



A KEY TO PRINCIPAL PLANT SUBSTANCES.* 



By Rodney H. Tri k. 



The following key is an attempt to arrange for ready use in the la- 

 boratory the simpler methods of identifying the commoner plant substances. 

 The device that has proved of service in the identification of plants seemed 

 to the compiler capable of adaptation to the present case, and an experi- 

 mental trial of this key in laboratory practice during the past two years has 

 seemed to confirm this thought. Standard works on microchemistry were 

 used in the preparation of the following, and no claim to originality in sub- 

 ject matter is made. 



The manner of use is so simple that explanation seems hardly necessary. 

 Confirmatory reactions, referred to in the key by numbers in parenthesis 

 accompanying tin- names of the substances, are appended and should be 

 made use of. 



One direction must lie strictly observed. Each separate reaction de- 

 mands a fresh section and a dean slide and cover glass. 



Zinc chloriodide. 



A.i Color red. 



R.i Col) contents Tannin. (1) 



B.ii Cell walls Lignin.t 



A. 11 Color brownish, eel] contents Protoplasm and Proteids. (2i 



A. in Color blue. 



B.i Amorphous muss Plant mucilage. (3) 



B.ii Granular cell contents Starch. 



A. iv Color violet. 



B.i Cell walls Cellulose. 



B.n Cell contents Tannin. (1) 



A.v Color yellow. 



Phloroglucin and HC1. 



B.i Rose-colored walls Lignin. 



B.n Uncolored. 



C.i Pnswelled cell walls Suberin. <4) 



C.n Swelled cell Avails or amorphous. 



P.i With iodine and H.SO^ blue Plant mucilage. (3) 



, ,,..,, . ,. . ,, on . , , . , t Proteids and 



P.n A\ ltb. iodine and II .SO . yellowish or brownish. J ^ 



2 « ( Protoplasm. (2) 



A. vi ]S'o color reaction. 



Trommer's reagent, do) 



B.i Orange-brown precipitate formed <Cu 2 0) Dextrose. 



B.n Deep violet color, no precipitate Cane sugar. 



B.in No visible reaction. 



* Reprint from Pharmaceutical Review. Jan. 1898. page 9. 

 + See for confirmation, test with phloroglucin and HC1. 



