METHODS OF ANALYSIS. 



with several portions of water, using not more than 15 cc in all. Use a feather or 

 rubber-tipped glass rod to remove the crystals that adhere to the flask. Allow the 

 double filter to drain, then apply water to the crystals, drop by drop, until they are 

 practically free from mother-liquor, and afterwards wash them, drop by drop, from 

 a pipette, with alcohol previously saturated with powdered morphine. When this 

 has passed through, displace the remaining alcohol by ether, using about 10 cc or 

 more, if necessary. Allow the filter to dry in a moderately warm place, at a tempera- 

 ture not exceeding 60 C. (140 F.) until its weight remains constant, then carefully 

 transfer the crystals to a tared watch-glass and weigh them. 



Place the crystals (which are not quite pure) in an Erlenmeyer flask, add lime 

 water (10 cc for each 0.1 gram of morphine) and shake flask at intervals during half 

 an hour. Pass the liquid through two counterpoised rapidly acting, plainly folded 

 filters, one within the other (the triple fold of the inner filter being laid against the 

 single fold of the outer filter), rinse the flask with more lime water and pass the 

 washings through the filter until the filtrate, after acidulating, no longer yields a 

 precipitate with mercuric potassium iodid T. S. Press the filters until nearly dry 

 between bibulous paper and dry them to a constant weight, then weigh the contents, 

 using the outer filter as a counterpoise. Deduct the weight of the insoluble matter 

 on the filter from the weight of the impure morphine previously found. The differ- 

 ence, multiplied by 10, represents the percentage of crystallized morphine contained 

 in the opium. 



