198 Composition of the Potato. 
superior to others, and it is also probably true that those which 
are inferior in their amount of starch may be the best for supply- 
ing the wastes of the body. 
The following analyses, which have been made in my labora- 
tory, will fulfil the design of this essay. 
1. Organic analyses of the Mercer potato, by Mr. J. Salisbury. 
The potato w^as sliced longitudinally through its middle, from 
the rose to its heel end. Organic analysis shows that it is com- 
posed of the following elements: 
Starch, - - - - 9-7 10 
Fibre, - - . . 5-779 
Gluten, .... -205 
Fatty matter, - - - -084 
Albumen, _ _ - - -249 
Casein, - - - - -506 
Dextrin, - > . . -074 
Sugar and extract, - - 3-931 
2M85 
Water, - - - - 79-508 
100-693 
As it is found that the ends of the potato constantly differ in 
omposition, and especially in the amount of water, the following 
exhibits quite strikingly this fact: 
Seed or rose end. Heel end. 
Water, - - - 83-839 75-177 
Dry matter, - - 16-161 24-823 
Ash, - - - - -727 -431 
Calculated dry, - 5-197 2-296 
Composition of the Ash. 
Ash of the whole potato, without regard to its ends. Analysis: 
Silica, ... - 4-400 
Lime, .... -180 
Magnesia, .... -800 
Potash, ... - 13-263 
Soda, .... 24-925 
Chloride of sodium, - - 11-606 
Sulphuric acid, ... 6-254 
Carbonic acid, _ _ _ trace. 
Organic matter, - . _ 2-536 
Phosphates, - - - 38-500 
102-434 
