GROUP XVI  . Phenol.—This includes a very large number of bodies chemically allied to benzol, such as carbolic acid, sulphocarbolates, creosote, wood tar, coal tar, oil of cade, thymol, salicylic acid, benzoic acid, naphthol, hydroquinon, cresol, guaiacol, ichthyol, saccharin and many others . These all resemble carbolic acid more or less closely, and may be described as general protoplasm poisons . Locally their destructive and irritating effects vary a good deal, but even when very dilute they all have a marked poisonous action on bacteria, white blood corpuscles, yeast and similar organisms . After absorption most of them exercise a depressing effect upon the nervous system, and are capable of reducing high temperature . They are mostly excreted in the urine .