The effects of the ulcerative action admit of greater variations than those of the inflammatory, and, therefore, more readily show the presence of specific action. The healthy ulcerative action exhibits certain appearances which have been already described, and which are easily known. The simple deviations which have been treated of, in considering the different genera of ulcers, are also discoverable by the effects, or peculiar symptoms. The specific deviations dependent upon the presence of previous specific inflammation, or the application of a morbid agent, after simple ulceration has been induced, may also, in many cases, be detected and ascertained, by the variations which take place in the aspect of the sore, the appearance of the granulations, discharge, &c.; but these variations and appearances consist so much in peculiar hues and qualities of the granulations, which we have no words to convey an idea of, that it is impossible to give an accurate description of a specific sore, but must see it in order to obtain an idea of it. We may indeed say, that a sore is ragged, has a fiery look, is surrounded with an erysipelatous margin, and discharges a thin fœtid matter, but still we shall not convey the idea of the specific appearance of the ulcer. It is this specific appearance alone which characterises a specific ulcer; and this, in each peculiar ulcer, is different; and a knowledge of it can only be obtained by an attentive examination of many sores. On this account, it is extremely difficult, in many instances, to distinguish a specific ulcer, because the discrimination depends altogether upon the recollection of the practitioner, and the improvement which he has made of his former observations. It is indeed, it may be thought, an easy matter to distinguish a simple ulcer by negative characters, or the want of the peculiar aspect; but, as this aspect is very arbitrary, and as the appearance of simple ulcers is, as has been already described, very various, it is difficult to say, without much judgment, whether the sore be simple or specific; for the appearance of the one and of the other run imperceptibly into each other. Even if it be ascertained to be specific, it is difficult often to distinguish betwixt particular specific diseases, in so much, that many are forced to take mercury for the cure of syphilis, who never had that disease. Besides the appearance of the sores, specific action likewise produces a perceptible effect upon the scab which covers them, or the cicatrix which is formed. Thus, scrophula is marked by a particular appearance of the cicatrix, or of the scab. The venereal ulcer has likewise a particular scab, and many cutaneous ulcers are best distinguished by the scab. Other actions produce no considerable ulceration, but only successive desquamation of the cuticle.