24 The Philippine Journal of Science i9i8 



acid with a normal solution of alcohol potash. The resulting 

 liquid was evaporated to dryness. 



For the "whole" tablets 100 grams of finely powdered glucose 

 are used with the potassium palmitate from 15 grams of pal- 

 mitic acid. Corresponding amounts are employed for the weaker 

 pellets. With the aid of a little distilled water, a homogeneous 

 pill mass is made and is promptly molded to avoid changes in" 

 consistency. Where molding must be done by hand, a Whithall 

 Tatum Company No. 2 tablet mold, which makes fifty pellets 

 at one time, has been found satisfactory. 



After being molded, the pellets are dusted with powdered talc ; 

 they are then dried, first in the air and then in a desiccator. 

 They are subsequently packed in glass tubes, which hold about 

 forty pellets and which are sealed with paraffin until desired 

 for use. 



The potassium palmitate pellets are standardized with a solu- 

 tion of calcium sulphate, prepared as follows from a saturated 

 solution of calcium hydroxide: The normality of the calcium 

 hydroxide is determined by titration with standard 0.1 N' sulphu- 

 ric acid. Into a 200 cubic centimeter volumetric flask are pipet- 

 ted 100 cubic centimeters of the calcium hydroxide solution, 

 and 1 cubic centimeter of phenolphthalein indicator solution is 

 added. The solution is acidified with normal sulphuric acid 

 and is then neutralized with 0.2 N alcoholic potash. Only a 

 very faint phenolphthalein coloration should be present. Re- 

 cently boiled, distilled water is now added to the mark. 



Five of the pellets to be standardized are crushed in a mortar 

 with a little distilled water, and phenolphthalein is added. This 

 solution is titrated with the calcium sulphate, prepared as above, 

 which is added drop by drop from a burette, with constant 

 stirring. The end point is the disappearance of the phenol- 

 phthalein coloration,® just as in the field determination. From 

 the mean of several such standardizations is calculated the 

 reacting value of the pellets. 



Unfortunately pellets of potassium palmitate lose their strength 

 rather rapidly and must, therefore, be restandardized at fre- 

 quent intervals. The exact cause of this deterioration is not 

 as yet definitely known, but from the data at hand, it appears at 



' It is essential, in preparing from palmitic acid the potassium palmitate 

 to be used for pellets, that neutralization be effected with the slightest 

 possible excess of alkali. If any appreciable amount of free alkali is present, 

 the alkaline reaction to phenolphthalein will be due- to this cause as well as 

 to hydrolysis of the potassium palmitate and will not, therefore, disappear 

 when an excess of calcium or magnesium salts is present. 



