After cooling, the contents of the flask are then transferred to the distilling flask with water, and to this 25 cubic centimeters of potassium-sulphide solution are added, 50 cubic centimeters of the soda solution, or sufficient to make the reaction strongly alkaline, and with a few pieces of granulated zinc. The flask is at once connected with the condenser and the contents of the flask are distilled until all of the ammonia has passed over into the standard acid contained in the precipitating flask previously described and the concentrated solution can no longer be safely boiled. This operation usually requires from 20 to 40 minutes. The distillate is then titrated with standard ammonia. The use of the mercuric-oxide in this operation greatly shortens the time necessary for digestion, which is rarely over an hour and a half in the case of substances most difficult to oxidize, and is more commonly less than an hour. In most cases the use of potassium permanganate is quite unnecessary, but it is believed that in exceptional cases it is required for complete oxidation, and, in view of the uncertainty, it is always used. Potassium-sulphide removes all mercury from solutions and so prevents the formation of mercuro-ammonium compounds which are not completely decomposed by soda solution. The addition of zinc gives rise to an evolution of hydrogen and prevents violent bumping. Previous to use, the reagents should be tested by a blank experiment with sugar, which will partially reduce any nitrates that are present which might otherwise escape notice. This method cannot be used for the determination of nitrogen substances which contain nitrate or certain albumenoids. These methods of analysis are suitable to all spices and have been used with them. They are but a general process, however, and are dependent for their value on uniformity in the way they are carried out and the manner in which peculiarities of proximate composition in different spices are considered in drawing conclusions; determinations of particular substances, such as piperine, require, however, modifications, which must be described when discussing the analysis of each separate spice. The chemical composition of olive stones and cocoanut shells is about as follows: Water, 5.63 6.15 Ash, 4.28 2.15 Fiber, 41.33 37.15 Albumenoids, 1.56 1.25 Nitrogen, .25 .20 ------------------------------------------------------------------------ [Illustration: BLACK PEPPER (Piper Nigrum) 1 Malabar 2 Acheen or Sumatra 3 Mangalore 4 Singapore 5 White, from Penang, with all three coats removed 6 White, with one coat removed 7, 8 Parts of spikes 9, 10 Fruit 12 Ovary with stamens 13 Stamens 14 Portion of spike 15 A flowering twig] CHAPTER IV BLACK PEPPER