33 



the deiermiiiuiion u>ini; a quantity sullicient to give the sample approximately the 

 sin-iiu'ili "i the standard, From this result calculate the amount of citral in the sample. 

 If tin- comparisons are made in .\ osier tubes, standards containing 1, 1.5, 2, 2.5, 3, 3.5, 

 and t mi; should be prepared and the trial comparison made against these, the final 

 . ompari-on brim; made with standards between 1.5 and 2.5 mg varying but one-fourth 

 iif a milligram. 



The I'nlin \viii-_' point- are to be especially noted : 



Tin- aldehyde-free alcohol (26 cc) on standing for 20 minutes in the cooling bath with 

 the fuchsin solution Mild develop only a faint pink coloration. If a stronger 



color i< developed, treat a-jain with metaphenylene-diaihin hydrochlorid. 



Jt i- absolutely essential \<> keep the reagents and comparison tubes at the required 



temperaiiir.-. 'omparisons should lc made within one minute after removing the 

 lulu-* from the hath. \Vh-n- the comparisons are made in the bath (this is possible 

 only when- the bath i> '_da )th- standards should be discarded within twenty-five 

 mimi .Hiding tin- fuchsin solution. Give samples and standards identical 



treatment. 



Not.- on samples colored with turmeric whether or not the color interferes with the 



come ' Mi samples '_' and .">, after making determinations on the samples sent, 



them, removing the colors as follows: After weighing the sample to be used for 



anal;- .ppen-d wei^hint; bottle, add a drop of concentrated hydrochloric 



acid and a -mall piece of fat-free \\oolen doth, stopper and allow to stand over night. 



ve the (loth wii>hinir wilh aldehyde-free alcohol and determine the citral in the 



colorle>s solution as u-ual. Repeat the above comparison heating the acidified 



I woolen doth under a reflux cooler for a lew minutes, cool, remove the 



cloth and d'-TeMuine the ciiral a- usual. 



-ample* sent were as foil. 



1. A 1 ii, oniainii .uns of !)f> per cent alcohol and 192 grams 



lemon oil, the whole colored with turmeric. 



, terpen.'li-.- exiM- i of lemon <t reiiu't lictied withcitral; 300 grams lemon oil 



dcohol; L',070 grams of water were-added and 



iiL'ht the precipitated oil was removed and 3.76 grams of citral 

 1. The \\hole colored with Niiphihol Yellow S. 



:al in dilute alcohol ("iO per cent volume) containing 3,000 

 . p. ciiral making the actual percentage of. citral 0.12 per 

 cent The whole . ,,|.,red with Naphthol Yellow S. 



ion of citral in dilute alcohol (~>i) per cent \>y volume) containing 3,500 

 hoi and .' c. |>. ciiral making the actual percentage of the latter 



The whole colored with turmeric. 



Th. ; in the following table: 



H-itrk <>n A t, nniii I ny ntrnl in lemon extracts, 1908. 



o Excluded from averages. 



. -Bull. I'.' 



