The Potato Disease. 521 
After all the examination and reasoning of Mr. Since, there 
seems to be only a remote probability that he has ascertained the 
cause of the Potato Disease. The conviction is likely to remain, 
that this is one of the inscrutable visitations by which Divine 
Benevolence chastises guilty nations and teaches them their de- 
pendence on him for their " daily bread." 
To the writer it has appeared far more probable that this is a 
disease, like the epidemics among men, and diseases of like nature 
among cattle or other animals, for which no adequate cause is 
known or which depend upon operations in nature which have so 
far been inexplicable. It will have its course like the Cholera, 
and in the same easy manner disappear under the operation of 
the benevolent arrangements of the Creator. 
The fact urged by Mr. Smee, that the diseased tuber will con- 
tinue the disease in the new plant appears to imply a cause which 
has a deeper seated origin than the action of insects on the leaves. 
At least a more extensive series of observations is required before 
this conclusion can be received. 
The Sweet Potato, which the botanists name Convolvulus batata^ 
and w^hich has a vine-form stem, was introduced into Europe and 
well known before the year 1600. This is the Potato intended 
by Shakspeare, and seems never to have been cultivated to much 
extent in England, and is at this time rare and dear in that 
country. 
The Common Potato, Solanum tuberosum of botanists, is a 
very different plant. It was first figured in Gerard's Herbal in 
1597, and is a native of South America, growing wild and bear- 
ing only small and indifferent bulbs or tubers. By cultivation 
the tuber is larger and more nutritious. It is not certain by whom 
it was introduced into England, though it is commonly ascribed 
to Sir Walter Raleigh. It was the cultivated Solanum of Europe, 
which was brought to these States, and has become of such vast 
consequence as an article of food. Many varieties have been 
cultivated in this country, and at the Horticultural Gardens, it is 
stated by Mr. Smee, "two hundred kinds" (varieties) are culti- 
vated, though not more than a tenth of these find a place in the 
markets of London. 
The nitrogenous products of vegetables, or those parts contain- 
ing nitrogen, are directly nutritious, and are found in very differ- 
ent proportions in the articles used for food by men. Thus 67 
pounds of Peas, 108 of Buckwheat, 111 of Rye, 177 of Rice, 
138 of Indian Corn, and 613 of Potatoes, are equivalent to 100 
pounds of Wheat Flour, as given by Mr. Smee p. 20. 
It is also stated by this author, that six pounds of Potatoes 
were alone an adequate daily allowance for a man, though an 
Irishman is said to eat several pounds more in a day. 
