Composition of the Potato. 197 
COMPOSITION OF THE POTATO. 
BY E. EMMONS. 
It is necessary, in making a proper estimate of the value of any 
article as food, that we should not give too much importance to a 
single element which it may contain. Starch, as is well known, 
abounds in the potato, and its nutrient value is supposed by many 
to depend principally upon its presence. This opinion, however, 
is not well sustained by experience, inasmuch as its sustaining 
powers are greater than is due to this element. Albumen and 
casein also exist in this vegetable, as well as inorganic matter, to 
which, along with starch, its value must depend. Hence, in the 
analysis of the potato, when it is designed to determine its value 
as food, it is quite essential that its albumen and casein, etc., 
should be determined, as well as its starch and sugar. This will 
appear in a clear light when it is known that albumen is one of 
the constituents of the blood, and one of the materials which sup- 
ply the wastes of the system of animals. Albumen and casein 
abound in those fluids and solids which appear to be designed to 
build up the original structures. Milk, the white of eggs, and 
other albuminous matters, are furnished to the young of all ani- 
mals, and though in some instances they appear to be of animal 
origin, yet when traced back to their sources, they are found to 
be derived from the vegetable kingdom. The property which 
distinguishes albumen is its coagulability by heat. Casein coag- 
ulates by acids. The blood coagulates when cold, after separa- 
tion from the body. The blood is an albuminous body. Albu- 
men as well as casein contain sulphur. The decomposition of the 
egg proves this by the formation of sulphuretted hydrogen, and 
proves, too, that it is not in the egg an oxidized body. Sulphur, 
too, enters into the composition of the most important organs. 
Sulphur, as an oxidized body, enters into the composition of the 
potato, though it is not clear that this statement is entirely free 
from doubts, for it is possible that the sulphuric acid is the oxid- 
ized sulphur of the albumen formed in burning. 
In addition, then, to starch, the potato contains several other 
important materials, which are capable of supplying the wastes 
which a living being is continually undergoing. 
It is not the purpose of this brief essay to show that different 
varieties differ in composition, and that some are better calculated 
to perform the part of a nutriment than others, but rather to exhi- 
bit the general composition of this vegetable. It is, however, 
undoubtedly true that the nutrient properties of some varieties are 
