In the drink and food, however, most observers have sought the exciting causes of scurvy. Instances have been reported where the disease seems to have depended upon the use of impure water, etc. The imagination has been tortured to seek in some quality or sort of food the specific origin of scurvy. With regard to quantity, it may be stated that in severe famines scurvy may or may not occur according as the food, though scant, is in due proportions of animal and vegetable, though it is true that the ordinary conditions of a famine preclude the procurement of succulent vegetables. The quality of the food has nothing further to do with the production of scurvy than by impairing the general health, for it has often happened that putrid food has been long used without scorbutic symptoms arising. The kind of food is equally {171} innocent, although various special articles have been charged with specific activity. The frequency of scurvy in Brabant was attributed by Ronseus to the use of aquatic birds; Sherwin and Nitsch assigned the same peculiarity to a free use of fish; and Henry Ellis to the too free use of spirits. Even the generally widespread and much-esteemed article of diet sugar was in disrepute with Willis. The too free use of salted meats has been often accused of causing the trouble. The fat rising on water in which salt provisions were boiled was considered by Cook and Vancouver to be of particular pernicious effect, and even the copper vessels in which they were cooked were condemned by Travis as able to communicate the scorbutic poison to the food. To the milk of animals browsing on verdure upon which pernicious dew had fallen was referred an epidemic which occurred in Silesia in 1591. Diseased potatoes were considered sufficient to determine scurvy in Ireland and Scotland by O'Brien.