substance, are found to be erroneous. Take another case--that of the disease known as "scurvy." The word "scurvy" means "afflicted with scurf, mean and dirty." It was applied to persons afflicted by this particular disease, and a Latin medical word, "Scorbutus," was made from it in the Middle Ages, which survives as "scorbutic" at the present day. Scurvy was formerly very common on board ship, in beleaguered armies, in prisons, and in other conditions in which men's food was limited to dried and salted, often badly preserved, meat and biscuit, or stale bread. Its real causation is not even now agreed upon: some holding that it was due to actual poisoning by the badly preserved food, others that it was due to the absence of certain elements--only to be obtained from fresh meat or fresh vegetables. Others think that it was caused by a bacterium. The victim of scurvy becomes much debilitated, the gums become spongy and ulcerated, and extravasations of blood are found in all parts of the body, often leading to ulceration. In the old times a whole ship's crew of the Navy would be attacked by it, and half or more died before a port could be reached and fresh food obtained. It was found that the use of fresh vegetables, fresh meat, and the juice of fruits prevented its outbreak, and cured it when once started. For one hundred and fifty years it has been held in check by the use of lime-juice as a drink whenever supplies of fresh vegetables and meat run short. It has now become so unusual a disease that there has been no proper study of it in the light of modern knowledge. It seems to be essentially the same condition of malnutrition as that which prevailed in cities and large tracts of country in the Middle Ages and occurs at the present day in Norway, caused by a diet of badly salted fish and dried meat. This produced ulceration of the extremities, allowing the leprosy bacillus to make its way through the broken skin into the tissues, and thus led to the widespread occurrence of leprosy. Whether bacilli of any kind were concerned in the old virulent outbreaks of "scurvy" on sailing ships must remain uncertain, but it is highly probable that they were. In any case, it is certain that the juice of fresh meat or of fresh vegetables when taken set going a better condition of nutrition in the body, and so acted as a preventive and a cure of scurvy. Some writers suppose that it was the salts, such as citrates and lactates, present in fresh fruits and vegetables which were effective in staying the disease; but this has by no means been proved, and is not, at the moment, accepted. It is probable that here, as in the case of Mr. Hopkins's rats, it was a quite minute quantity of a readily-destroyed proteid present in fresh meat and vegetables which was necessary to keep the chemical processes of nutrition in healthy activity.