[Vol. 6 



104 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



rion of the relative amounts of tannins present. Five cc. of 

 the various aqueous extracts were placed in clean test-tubes 

 of 18 mm. diameter, four drops of a 2.0 per cent aqueous solu- 

 tion of ferric chloride added to each, and the color determined 

 by comparing them with Ridgway's ('12) plates. 



TABLE VIII 



RELATIVE AMOUNTS OF TANNINS PRESENT IN THE AQUEOUS EXTRACTS 



Flask no. 



45,46,47 



1,2,3 



4,5,7 



8, 9, 10 



11, 12, 13.... 



Control (distilled water) 



Not autoclaved 

 45 minutes 



I hour, 45 minutes 



II hours 

 21 hours 



Wood -brown 

 Yew-green 

 Kronberg's green 

 Wood-brown 

 Wood-brown 

 Yellow tint 



Order of 

 intensity 



3 

 1 

 2 

 3 

 3 



This would seem to indicate that the extracts from the wood 

 autoclaved the longest intervals and the extract from the wood 

 not autoclaved contained the least tannin, while that auto- 

 claved for forty-five minutes contained the most. Comparing 

 these results with the table showing the amounts of reducing 

 substances in the various aqueous extracts it is found that they 

 in no way coincide. 

 • The presence of lignin in the aqueous extracts. — A test for 



the presence of lignin in the various aqueous extracts was 



made with phloroglucin and hydrochloric acid. In no case 



was more than a faint pink color evident. When, however, a 



few cc. of ether were added, the mixture well shaken, the ether 



separated and evaporated, the residue gave a decided red color 



with phloroglucin and hydrochloric acid. All of the extracts 



gave a positive test when treated in this manner. 



The presence of coniferin in the aqueous extracts. — When 

 an aqueous solution of phenol and hydrochloric acid was 

 added to the extracts in no case did a color reaction take place. 



Hydrogen ion concentration of the aqueous extracts. — The 

 hydrogen ion concentration of the extracts was determined 

 according to the method suggested by Sorensen ( '09) as modi- 

 fied by Henderson ( '09) and previously employed by Duggar 



