When this disease once appears it is apt to spread over wide areas where the same climatic influences prevail, and when the disease appears in any strength the crops are rapidly rendered unfit for human food. The trouble of the Irish peasantry of the West is that they have no alternative crop to fall back on when the potato fails. Their plots are too small for cereals, and they cannot be persuaded to cultivate cabbages and other vegetables along with their tubers. It is thus that, when the day of tribulation comes, the potato appears to be really a curse rather than a blessing to agricultural Ireland.
There have been frequent projects for reverting to original types--that is to say, for obtaining a fresh supply of the indigenous plant from South America, and breeding a new stock, as it were. It is a possible mode of extirpating the disease which may be resorted to.
The Irish famine of 1847 was due to the failure of the potato crops in 1846, preceded by two or three years of bad crops. This failure was due to disease, and the eating of the diseased tuber brought on a pestilence, so that altogether the deaths by starvation and epidemics in that disastrous period amounted to nearly a million and a quarter persons. To deal with the distress various sums were voted by Parliament to the total amount of over ten millions sterling. This was supplemented by private philanthropy in this country, and by generous aid from the United States and some European countries. What was the actual money cost to the world at large of the failure of the Irish potato crop in 1846 can never be accurately known; but the amount was so enormous as to create a serious economic problem in connection with the homely tuber.
There have been several partial failures since in Ireland, although nothing so extensive as that of 1846, and in 1872 the disease was very bad in England. In that year, indeed, the importation of foreign potatoes rose to the enormous value of one million six hundred and fifty-four thousand pounds to supply our own deficient crops. In 1876, again, there was great excitement and alarm about the 'Colorado beetle,' an importation from America, which was destined, it was said, to destroy all our potato-fields. But the beetle proved comparatively harmless, and seems now to have disappeared from these shores.