The most common example of the direct transmission of disease from animals to men is through the development of the parasite in a pig, known as "trichinosis." This disease is due to a minute worm scarcely visible to the naked eye which lives in the muscles of men, dogs, swine, and other animals, and also under other conditions in their intestines. Millions of the young trichinae may live in the flesh of a pig without producing any particular difference in the appearance of the flesh. After four or five weeks, they become incased in small white spherical capsules which later, after a year or so, become entirely calcified. In this form they live for years in the flesh of the pig and do no harm in that condition. If, however, this flesh be eaten by man without being cooked so thoroughly as to destroy the little worm (about one twenty-fifth of an inch long) which has been living in these capsules, then they become distributed around the stomach of the person eating that flesh, enter the intestines, and attach themselves to the membranes there. They grow very rapidly, and broods of from 500 to 1000 young worms are produced from each one of the entering worms, and, since there may be a quarter of a million or more in an ounce of pork, it is not surprising that the total number deposited in the intestines from a single meal of raw pork is enough to produce great distress, characterized by vomiting and diarrhea. Fortunately, the disease is not necessarily serious, since after the development of the young worms (and it is at this period when the suffering of the human patient is at its height), the worms begin to form capsules again, as in the pig, and when inclosed, are again inocuous. Professor Sedgwick says that persons in robust health may be able to survive the attack of half a million or more of these flesh worms and recover, but there is a limit to human endurance, and the numbers often contained in the muscles of man from this source are almost incredible. In some severe cases, the numbers contained in human bodies have been estimated by reliable authorities to be as high as forty to sixty millions. Not long ago, the writer was impressed with the severity of this disease by having brought to his attention an epidemic in a herd of swine caused, presumably, by feeding waste which contained rinds of Western pork, infected with trichinae and many examples may be found of regular epidemics caused by persons eating raw ham infected with this disease. Fortunately the means of prevention is very simple and implies merely the thorough cooking of the meat. If persons will avoid eating raw or underdone swine flesh in any of its varieties, no danger need be apprehended.