326 



THE FARMER'S MAGAZINE. 



THE CHEMICAL PROPERTIES OF THE POTATO, 



AND ITS USES AS A GENERAL ARTICLE OF COMMERCE WHEN PROPERLY MANIPULATED. 



[Read before the British Association for the Advancement of Science.] 



It IS the impression in the United Kingdom generally 

 that the potato is simply a useful vegetable, well suited 

 to be boiled, baked, or mashed ; but beyond that, its 

 properties and uses are little, if at all, known — certainly 

 not amongst the so-called public ; and it is only within 

 recent years that any use whatever was made of it as an 

 article of manufacture. 



In the year 1834 the article of farina starch, for dress- 

 ing muslins, was first manufactured from it in Ireland, 

 which increased until the year of the potato blight, 1846, 

 when it ceased, but is now again in practice. Beyond 

 this, and its sale as household starch — for instance, the 

 Glenfield starch — and not a little as " Indian arrow- 

 root," its produce is, in fact, unknown to the commerce 

 of this country. 



Abroad it is not so. In France farina is largely used 

 for culinary purposes. The famed gravies, sauces, and 

 soups of France are largely indebted for their excellence 

 to that source ; and its bread and pastry equally so : 

 whilst a great deal of the so-called Cognac imported 

 into England from France is the produce of the potato. 

 Throughout Germany the same uses are common ; and 

 in Poland the manufacture of spirit from the potato is 

 a most extensive trade. " Stettin brandy," well known 

 in commerce, is largely imported into England, and is 

 sent from thence to many of our foreign possessions 

 as the produce of the grape, and is placed on many a 

 table in England as the same ; whilst the fair ladies of 

 our general country perfume themselves with the spirit 

 of potato under the designation " Eau de Cologne." 



But there are other uses which this despised esculent 

 is turned to abroad. After extracting the farina, the 

 pulp is manufactured into ornamental articles, such as 

 picture-frames, snuff-boxes, and several descriptions of 

 toys ; and the water that runs from it in the process of 

 manufacture is a most valuable scourer. For perfectly 

 cleansing woollens, and such-like articles, it is the 

 housewife's panacea ; and if the washerwoman happens 

 to have chilblains, she becomes cured by the operation. 

 Now all the uses I could ever discover for the potato 

 in Ireland in former times, beyond that of boiling, is 

 summed up in a song which lauded the properties of a 

 certain variety called the " Buck Potato," in great esti- 

 mation at the time that the ladies of Ireland wore " high- 

 call'd caps :" each verse ends — 



" Then cat the buck in two. 

 And 'twill make you starch and blue 

 For your high-call'd cap," 



which possibly suggested the use to the proprietor of 

 the Glenfield starch. 



But I neither seek the manufacture of brandy, eaude 

 Cologne, picture-frames, nor toys from the potato. 



What I desire is to see it converted into a staple article 

 of food ; and if I can enlist in my views the support of 

 the scientific, I would hope for a good result : hence 

 why I do myself the honour of addressing this section. 



We all know that food of a description suitable to 

 support mankind in health, must contain three special 

 constituents, viz. : — 



First, starch, sugar, gum ; 



Second, oily substances ; 



Third, albumen, gluten, &c. 



And I may say that the only vegetable substance of gene- 

 ral commercial use, which is supposed to contain these 

 elements in proper proportionate quantity as food for 

 man, is wheat. Oats are assumed to have too much oil ; 

 whilst peas and beans are said to have too much gluten. 

 And there are many facts to prove that animals fed solely 

 on these or other individual substances soon cease to 

 live. 



Dogs fed on gelatine alone speedily die ; fed on 

 wheaten flour, they close their lives in some 50 days. 

 Rabbits and guinea pigs, fed solely on oats, solely on 

 barley, cabbage, carrots, &c., usually die in 15 days. 

 Yet it is a fact beyond all dispute that, up to the period 

 of the potato blight, the Irish cottier peasants, amount- 

 ing to perhaps one-half of the whole population, lived 

 to a good old age, and reared large families, fed upon 

 the potato alone ! 



The natural inquiry that strikes the mind is, what 

 are the constituents of the potato, to produce such re- 

 sults ? 



It is a fact that the potato contains some 75 per 

 cent, of water ; but what does the residue contain ? 

 What are the actual nutritive components ? They are 

 as follow : — 



Of starch . . 



„ gluten ., 



„ oil 



And what are the nutritive constituents of wheat ? 

 Of starch .. .. 78.199 per cent. 



„ gluten .. .. 17.536 „ 



„ oil .. .. 4.265 „ 



Thus we find that the essential elements of nutrition 

 are identical in the potato and wheat, whilst the small 

 deficiency of gluten and oil (bone-and-sinew-producing 

 matter) is compensated by the increase of starch (flesh- 

 and-fat-producing matter). And it is unquestionable 

 that the oil and gluten of wheat rest principally in that 

 part of the grain which is not used for human food, 

 namely, the bran and pollards ; whilst the entire dry 

 matter of the potato is suited for conversion into food 

 of several kinds. 



With such facts to guide us, is it not reasonable to 

 inquire— Why should the potato be used merely as a 



84.077 per cent. 

 14.818 „ 

 1.104 „ 



