16 JOURNAL OF THE 



on a sand-bath and the heat continued until the excess of acid 

 was driven off and the residue assumed a white appearance. 

 This was then moistened with very diUite hydrochloric acid 

 (1 : 100), a few drops of tincture of turmeric were added, and 

 the entire mass dried down on a water-bath. The appearance of 

 the cherry-red or cinnabar-red coloi* was taken as an evidence of 

 boracic acid. The residue was then used for the flame tests. 

 This was made by placing a part of it upon a strip of platinum, 

 moistening with alcohol and igniting. The green flame flashes, 

 best observed by blowing out and relighting the alcohol, were 

 regarded as confirmatory of the turmeric tests. The flame test 

 is, however, not so delicate as the latter, as has also been observed 

 by Crampton. 



The relative and absolute delicacy of these tests was also 

 approximately determined. The flame reaction was still clear 

 with .01 gm. of boracic acid, but could not be gotten with .001 

 gm. This latter amount gave the color reaction, but .0001 gm. 

 failed to give it. 



These figures apply, of course, only to boracic acid treated 

 under like circumstances to the ash. 10 cc. of a solution of 

 boracic acid of knowMi strength was eva[)orated in a small j)orce- 

 lain dish and the residue mani[)ulated exactly as in Meisell's test. 



The porcelain dishes used in this research, and other apparatus 

 where the presence of boracic acid might be suspected, were care- 

 fully tested and shown free from anything that could conflict 

 with the tests. 



The appended table gives the substances examined and the 

 results of tfie tests. In many cases the tests were carefully 

 repeated to insure accuracy. The specimens were chosen so as 

 to represent as many diflerent classes of plants as possible. In 

 the case of caustic alkalies the evaporation and testing were done 

 in platinutn vessels. 



The experiments with various chemicals, pure and commer- 

 cial, were begun with the idea of seeing whether those which 

 might have come from some plant source, contained this sub- 

 stance so generally present in the plants themselves. The caustic 



