They have nothing to apprehend from the atmosphere, if attention is paid to the maintenance of its purity,—such as is necessary in other situations, as well as in the sick-room. Never brought into that immediate contact with the poisons which is necessary for their propagation, they stand in need of no directions for their removal or counteraction. Those persons, on the other hand, who are called upon to touch the patient and his clothes, are exposed to danger; and they should lessen its amount, by instantly putting their hands into warm water, and by freely washing them, with the assistance of soap,—and that ablution should be performed after each instance of contact. I have often had occasion to feel the pulse of persons ill of the worst forms of confluent and black small-pox, and any risk that has thereby been incurred, has been removed or remedied by immediately washing the hand as directed. In addition to washing, after that process is done, a small quantity of a strong smelling liquid, such as Lavender water or Eau de Cologne, should be poured into the hands. Their grateful odour may hide or cover that of the apartment, which the attendant may mistake for contagious air, as is often done, and thereby remove groundless apprehension. These seem to be the chief precautions that are necessary for meeting the dangers of contagion, if there is included what is sometimes used, viz. a covering for the hand,—a glove and the like,—which, as being harmless, and such as may possibly be useful, should be employed; and likewise the avoiding of eating and drinking with the same instruments and vessels used by the sick persons. The propagation of disease by contagion, in the modes already stated, though it can take place, and though it sometimes does take place, still there are the strongest grounds for supposing it a comparatively rare occurrence. I have already shewn, at the beginning of this work, that in one form, the atmospheric, contagion never operates, and I am now prepared to assert, that in the two forms in which alone it can act, that the instances of its undoubted agency are by no means nearly so common as they are commonly believed to be, especially in connexion with those acute diseases, accompanied with fever. It is my belief, founded on much observation, study, and reflection, that almost all cases of those contagious diseases, arise from causes or circumstances connected with those great agencies already detailed at full length, as inductive of pestilence in general, and of a nature epidemic, endemial, meteorological, and the like. I am led to the opinion, that this course of origin, even in contagious diseases, is the rule, and that the origin of disease, by contagion, whether contactual or mediate, is the exception. The grounds of this opinion are,—