In making these researches, it will be necessary to establish one important distinction; that is, 1st. that certain textures, as the osseous, the muscular of animal life, &c. are precisely the same in all the organs in which they are found, and consequently that their diseases must be the same; 2d. that others, as the cutaneous, the serous, the mucous, &c. experience, according to the organs to which they belong, some variety of structure and vital properties, which necessarily modify the general phenomena of the class of diseases that belong to these textures; 3d. that others, as the glandular, the muscular of organic life, &c. are very different in each organ; and that their general symptoms and class of diseases must consequently differ considerably. After having shown most of the local diseases, as affecting almost always, not an individual organ, but some texture in an organ, it is necessary to show the differences they present according to the textures they affect. As under each system, this subject will be treated more or less fully, I shall only refer to it here. We shall see, then, that pain is modified differently in each texture, according to the degree of sensibility that it possesses. No one excites the same sensations as the others when it is inflamed. Compare the burning of erisypelas with the throbbing of phlegmon, the pain of rheumatism with that of inflamed lymphatic glands, &c. We shall see also that the sense of heat, developed in each inflamed texture, has a particular character; here it is sharp and biting, there like the feeling produced by fire, &c. There are two general causes that produce a variation in the symptoms of diseases: 1st. the nature of the affected texture; thus, as I have just said, the inflammation of each produces a different kind of suffering. 2d. The nature of the disease; we know that cancer, whatever texture it may affect, has a pain that is peculiar to it; that syphilis and scurvy have also a peculiar character, that is, however, modified in a slight degree in each texture.