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same morbid change when introduced into the system. If these experiments had been made twenty years later the original statements might have gone forth as established truths; but science was then less trammelled. Burdon Sanderson, Wilson Box and others tested the theories that had been broached. It was found that although the experiments were true, that tubercle could be artificially produced, it did not require tubercle to be used, that other animal substances, that vegetable irritants, and still more that a mere wound would suffice under certain conditions. That these irritants when placed within the tissue became surrounded by product of a cheesy and inflammatory character, and that the subsequent changes in these products in a diathesis of a tubercular type led to secondary deposit of an advanced character in connection with the lymphathic system. It is true that some guinea pigs were used to establish these most interesting and important pathological truths; mere reasoning would have misled, the advance of science was due to direct exper-
