122 PLANT PRODUCTS 



Potatoes. — The potato, although well known and 

 popular to-day, is a very recent introduction into general 

 use. It is cultivated entirely from the tuber itself, and 

 not from the seed of the plant. The true seed of the plant 

 produced from the flowers does not yield usable potatoes 

 for two or three years, after which time new varieties of 

 potatoes are obtained and have often fetched extravagant 

 prices. The old varieties, in process of time, tend to die out. 

 From the strictly botanical point of view, it must be remem- 

 bered that all the potatoes of one kind in the world are really 

 one single plant. They have all come from one single true 

 seed, and, like all living things, the individual, in process of 

 time, dies, and there appears, therefore, to be a limit to the 

 life of any particular so-called variety of potato, since each 

 variety is only an individual. The potato loves much 

 manure, especially farmyard manure, but also gives good 

 results from the use of sulphate of ammonia and super- 

 phosphate and sulphate of potash. Good cultivation is 

 also essential for big crops. It is a crop which is particularly 

 suited to small types of cultivation. It appears to grow in 

 most types of soil, though it likes a fairly open kind, but 

 plenty of spade work and manure will go a long way to 

 remedy any excessive heaviness a particular soil may possess, 

 and sprouting the potatoes before planting will reduce risk 

 from early frosts. Five to eight tons per acre of potatoes 

 represent about ordinary farm experience. Six to eleven 

 tons per acre are recorded as market garden results. The 

 potato contains about y^ per cent, of water, 20 per cent, of 

 carbohydrates, and 18 per cent, of starch, but higher figures 

 for solids can be obtained, especially where the manuring 

 has not been so generous. In the uncooked state potatoes 

 often prove slightly irritating when eaten, but when cooked 

 this difficulty is removed. Potatoes can be dried by 

 machinery for the production of potato flour. They can 

 also, after pulping or rasping, be used for the manufacture 

 of starch. Potato starch, after fermentation, is used for 

 the production of alcohol. 



In comparing the relative values of maize and potatoes 



