124 BOTANICAL MICROTECHNIQUE. 



that it reduces iodic acid ; and that it is colored red-brown 

 by a 2% solution of titanic acid in sulphuric acid, or deep 

 violet by a solution containing five drops of methylal 

 (CH 3 (OCH 3 ) 2 ) to a ccm. of concentrated sulphuric acid. 



2. Narcotine, CaaHaaNOr. 



Clautriau deduces the presence of narcotine in the latex 

 from its becoming colored reddish orange with a solution of 

 sodium selenate in sulphuric acid, as also happens with mixt- 

 ures of morphine and narcotine. Besides, it gives a precipi- 

 tate with palladous chloride and with iriaous chloride, while 

 morphine and codeine give no precipitate with the former, 

 and but a slight one with the latter reagent. 



3. Narceine, C 23 H 29 NO 9 . 



According to Clautriau, a yellow color following the addi- 

 tion of the solution of methylal, mentioned under " Mor- 

 phine," indicates the presence of narcei'ne in the latex. 



*'. Piperine, C n H 19 NO 3 . 



2I7a. Piperine, which has been recognized in the fruits of 

 various Piperacece, is slightly soluble in boiling water, more 

 easily soluble in alcohol than in ether, readily soluble in 

 benzol, insoluble in dilute acids. 



For its microchemical recognition concentrated sulphuric 

 acid may be used. This dissolves piperine with a yellow 

 color which later becomes dark brown, and, after 20 hours, 

 greenish brown (Husemann I, 491). But, since various other 

 ^substances give the same reaction, it can only be of value as 

 .negative evidence through its failure to appear. 



We owe to Molisch (I, 27) a very useful method of recog- 

 nizing piperine microchemically. A drop of alcohol is first 

 placed on the sections on the slide and dissolves the piperine. 

 Then the sections are covered with a cover-glass, and the 

 alcohol is allowed to evaporate until it occupies only about a 

 quarter of the space under the cover. Then water is added 

 and causes at once a strongly milky turbidity, if sections of 



