III.—=Meat injuries from the food eaten before killing.=—Pheasants fed on laurel, hares on rhododendron chrysanthemum, and other animals fed on the lotus, wild cucumber, and wild melon of Australia, have caused dangerous symptoms.
IV.—=Fish=, especially some kinds, occasionally produce nettlerash and other disorders, especially in warm weather. Leprosy has been ascribed to the eating of decomposing fish, but it occurs in countries where a fish diet is impossible.
Shell-fish and crustaceans (as lobster, crab) are very prone to produce evil results. Shell-fish (mollusca), such as mussels, cockles, and oysters, are dangerous foods. They are generally grown in estuaries, to which the sewage of towns has access; and not infrequently cases of enteric (typhoid) fever, as well as more acute attacks of diarrhœa and vomiting, have been traced to them. Mussels and cockles are seldom sufficiently cooked to render them safe; and oysters are eaten raw. They should never be eaten, unless from personal direct knowledge it is certain that they have been derived from an estuary in which there was no possibility of contamination by sewage.
V.—=Milk= has been a common carrier of disease. Cows eating the rhus toxicodendron get the “trembles,” and their milk produces serious gastric irritation in young children. The milk of goats fed on wild herbs or spurgeworts has produced severe disorders.
The milk of animals suffering from foot-and-mouth disease, although frequently drunk with impunity, occasionally produces inflammation of the mouth (aphthous ulceration). The milk derived from cows fed on grass from sewage farms is, _per se_, as wholesome as any other, and its butter has no more tendency to become putrid than that derived from any other source.
The great dangers in respect to milk are of its becoming mixed with contaminated water; or of its absorbing foul odours. The absorptive power of milk for any vapour in its neighbourhood, is shewn by exposing it in an atmosphere containing a trace of carbolic acid vapour: the milk speedily tastes of the acid.
Milk also tends to undergo rapid fermentative changes, especially in warm weather, or when tainted by traces of putrefying animal matter. Diarrhœa in children is frequently due to such a condition, or to the rapid decomposition of milk in an imperfectly cleaned bottle. Milk should always be boiled in warm weather; and it should never be stored in ill-ventilated larders, or where there is a possibility of the access of drain effluvia; nor ought it to be kept in lead or zinc vessels.