Roots. 



27 



Arranged in groups according to the chief classes of food-con- 

 stituents, the average composition of potatoes may be expressed 

 as follows : 



It follows from these average results that good potatoes consist 

 of f of water, and i of solid matter. Occasionally the proportion 

 of water in potatoes rises as high as 80 per cent. : the best mealy 

 potatoes often, on the contrary, contain but 70 per cent., and even 

 68 per cent, of water. With the variations in the amount of water 

 and solid matter, the proportions of the various constituents com- 

 posing the solid matter must, of course, be subject to more or less 

 considerable variations. Thus, whilst one sample of potatoes yields 

 from 15 to 16 per cent, of starch, another may yield only 12 per 

 cent. ; or whilst one kind contains 2^ per cent, of flesh-forming 

 constituents, another contains only H per cent. On account of 

 these variations in composition it is extremely difficult to attach a 

 precise nutritive value to potatoes. No kind of agricultural pro- 

 duce is liable to greater changes in composition, a circumstance 

 which, I believe, well explains the diversity of opinions which 

 practical men entertain with respect to the feeding qualities of 

 potatoes. But though it is impossible to state in precise language 

 what is the feeding value of potatoes, it may be observed that they 

 are beyond dispute the most valuable of all roots grown for food, 

 and especially well adapted for fattening purposes. 



In general it may be remarked in this place, that for all prac- 

 tical purposes the comparative nutritive value of different roots 

 may be estimated with tolerable accuracy by the amount of water 

 which the various species contain. Following this simple rule 

 we obtain, as the most nutritious of roots, potatoes ; next follow 

 parsnips, then carrots, after which mangold follows ; next we 

 have swedes, and last turnips. Practical experience, if I am not 

 mistaken, has shown that the different roots follow each other as 

 regards their nutritive value in the same order, namely, 1. 

 Potatoes; 2. Parsnips; 3. Carrots; 4. Mangolds; 5. Swedes; 

 6. Turnips. 



Parsnips and Carrots. Parsnips and carrots are justly es- 

 teemed as valuable feeding-substances, which are in this country 



