introduction of maize into Lombardy at an interval of two or three

generations, and its distribution corresponds closely to the poorer kinds of maize on colder soils, and to the class of the peasantry who get the worst kind of corn or meal for their food. The cases of the disease among the peasantry of Lombardy and some other maize-growing provinces of Northern Italy, were about one hundred thousand when last estimated; the endowed charitable houses and lunatic asylums are full of them. The connexion of the disease with its causes is perfectly well understood; but the economic questions of starvation wages, of truck, of large farms with bailiffs, and of agricultural usage, have proved too much for the chambers of commerce and the Government; so that there is as yet little or no sign of the decline of pellagra in the richest provinces of Italy. This disease is not mentioned in the Bible, therefore it has no traditional vogue; it is not well suited to knight-errantry, because it is a common evil of whole provinces; its causes are economic and social, therefore there is no ready favour to be earned by systematic attempts to deal with them; and there is absolutely no opening for heroism and self-sacrifice of the more ostentatious kind. These are among the reasons why this great object-lesson of a chronic disorder of nutrition, proceeding steadily before our eyes, has been so little perceived. It is in pellagra, however, that we find the key to the ancient problem of leprosy. The two diseases are closely allied in the insidious approach of their symptoms, in their implicating the tissue-nutrition through the nerves, or the nervous functions through the nutrition, in their cumulating and incurable character, and in their transmissibility by inheritance. Thus nosologically allied, they may be reasonably suspected of having analogous causes; and as we know the cause of modern pellagra to be something noxious in the habitual diet of the people, we may look for the cause of medieval leprosy in something of the same kind. The dietetic cause is not far to seek, and it cannot be stated better than in the following well-known passage by the philosophical Gilbert White in his _Natural History of Selborne_[206]:-- “It must, therefore, in these days be, to a humane and thinking person, a matter of equal wonder and satisfaction, when he contemplates how nearly this pest is eradicated, and observes that a leper is now [1778] a rare sight. He will, moreover, when engaged in such a train of thought, naturally inquire for the reason. This happy change perhaps may have originated and been continued from the much smaller quantity of salted meat and fish now eaten in these kingdoms; from the use of linen next the skin; from the plenty of bread; and from the profusion of fruits, roots, legumes, and greens, so common in every family. Three or four centuries ago, before there were any enclosures, sown-grasses, field-turnips, or field-carrots, or hay, all the cattle which had grown fat in summer, and were not killed for winter use, were turned out soon after Michaelmas to shift as they could through the dead months; so that no fresh meat could be had in winter or spring. Hence the marvellous account of vast stores of salted flesh found in the larder of the eldest Spencer even so late in the spring as the 3rd of May (600 bacons, 80 carcases of beef, and 600 muttons)[207]. It was from magazines like these that the turbulent barons supported in idleness their riotous swarms of retainers, ready for any disorder or mischief. But agriculture is now arrived at such pitch of perfection, that our best and fattest meats are killed in the winter; and no man needs eat salted flesh, unless he prefers it, that has money to buy fresh. “One cause of this distemper might be no doubt the quantity of wretched fresh and salt fish consumed by the commonalty at all seasons as well as in Lent, which our poor now would hardly be persuaded to touch.... The plenty of good wheaten bread that now is found among all ranks of people in the south, instead of that miserable sort which used, in old days, to be made of barley or beans, may contribute not a little to the sweetening their blood and correcting their juices.” Let us add to this, that the meat diet of the poorer class, whether serfs or freemen, would be apt to consist of the more worthless portions, the semi-putrid pieces in the salted sides of bacon, mutton or beef, and that badly-cured pork was in many parts the usual kind of flesh-food; and we shall have no difficulty in finding the noxious element in the diet of the Middle Ages, which the dietetic hypothesis of leprosy requires. Some who have advocated that hypothesis for modern leprosy, have laid themselves open, notwithstanding the ability and industry of their research, to plausible objections which have no bearing if the hypothesis be sufficiently safe-guarded. Leprosy, like every other _morbus miseriae_, needs a number of things working together to produce it, its more or less uniform specific character or distinctive mark being determined by the presence of one factor in particular. The special factor should be generalised as much as possible, so as to cover the whole circumstances of leprosy: it is not only half-cured or semi-putrid fish[208], but half-cured or semi-putrid flesh of any kind. The most general expression for leprosy is a semi-putrid or toxic character of animal food, just as for the allied pellagra, it is a semi-putrid or toxic character of the bread or porridge. Moreover it is that noxious or unnatural thing in the food, not once and again, or as a _bonne bouche_, but somewhat steadily from day to day as a chief part of the sustenance, and from year to year. As the rain-drops wear the stones, so the poison in the daily diet tells upon the constitution. Once more, such special causes may be present in a country generally, among the poor of all the towns, villages and hamlets, and yet only one person here and there may show specific effects that are recognisable as a disease to which we give a name. Unless there be present the aiding and abetting things, the special factor will hardly make itself felt; and if there be not the special factor, there may be some other _morbus miseriae_ but there will not be that one. These aiding things are for the most part the usual concomitants of poverty and hardships, wearing out the nerves far more than is commonly supposed and producing in ordinary an excessive amount of nervous affections among the poor. But among the poor themselves, as well as among the well-to-do, there are special susceptibilities in individuals and in families. One person may have the same unwholesome surroundings as another and the same poisonous element in his diet, but he may fall into no such train of symptoms as his leprous neighbour because he is not formed in quite the same way, because he has “no nerves,” or is of a hardier stock, or because his unwholesome manner of life comes out in some other form of disease (scrofula perhaps, less probably gout), or for some other reason deeply hidden in his ancestry and his personal peculiarities. The chances would be always largely against that particular combination of factors needed to make leprosy. It was a _morbus miseriae_ of the Middle Ages, but on the whole not a very common one; and it was easily shaken off by the national life when the conditions changed ever so little. It was all the more easily shaken off by reason of the facilities for divorce, the prohibition of marriage, and the monastic discipline. The staple diet as a cause of leprosy was suspected in the Middle Ages, and by writers as ancient as Galen. It is not without significance that the minute directions for the dieting of the lepers in the rich hospital of Sherburn, near Durham, urge special caution as to the freshness of the fish: when fresh fish was not to be had, red herrings might be substituted, but only if they were well cured, not putrid nor corrupt. Those directions were in accordance with the best medical teaching of the time on the dietetics of leprosy, or on how to prevent leprosy, as it is given with considerable minuteness in Gordonio and Gilbert[209]. On the other hand we find a singular ordinance of the Scots Parliament at Scone in 1386, or some forty years after the date of the Durham regulations: “Gif ony man brings to the market corrupt swine or salmond to be sauld, they sall be taken by the Bailie and incontinent without ony question sall be sent to the lepper-folke; and gif there be na lepper-folke, they sall be destroyed alluterlie[210].” Nothing could be more significant for the prevalence and persistence of leprosy in Scotland[211]. Putrid fish and pork did actually come to market; the dangers of them as regarded the production of leprosy were unsuspected; and the lepers (genuine or mistaken) were actually directed to be fed with them. Such food for “lepers” could only have fed the disease; and if it be the case that genuine leprosy was met with in Edinburgh and Glasgow more than two centuries after it ceased to be heard of in England, we need be at no loss to assign the reason why the disease was more inveterate in the one country than in the other.