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XXI] When possible the subject of undulant fever would do well to avoid the endemic area for one or more years after recovery.

Prevention.— Though mules, asses, oxen, cows, rabbits, and fowls can convey the micrococcus, there is no longer any doubt that goat's milk is the principal medium through which undulant fever is communicated to man.* This discovery has led to very striking and important results.

On the recommendation of the Mediterranean Fever Commission, the use of the milk of the Maltese goat was interdicted in the naval and military forces of that island. Immediately the incidence of undulant fever began to drop in the Navy from an average of 240 per annum up to 1906, to 3 in 1910, and in the Army from a previous average of 315 per annum to 9 in 1907. In 1909 the health authorities in Malta were authorized to kill all goats whose blood or milk gave the M. melitensis reaction. The goat population of the island was consequently reduced from 17,110 in 1907, to 7,619 in 1910. Concurrently the fever incidence in the civil population fell from an annual average of 632 to 318 (Eyre). These facts suffice to indicate the direction preventive measures should take. It must be borne in mind that certain products of milk cheese, butter, etc. may communicate the germ, and, further, that infected goats may appear to be in perfect health and may milk satisfactorily.†