We have sometimes thought, from the consideration of such circumstances, that there is something like a community of disposition causing members of the same family to be similarly affected by like agents, more than subsists between men who are unconnected:—something like an idiosyncrasy, which goes to make them suffer after the same fashion. There are such things as family characters, family idiosyncracies, family dispositions, family peculiarities of bodily conformation, and family temperaments; and may there not exist some family disposition, to be similarly affected by like circumstances? The case appears well worthy of philosophical inquiry, something beyond the untenable puerilities of Mesmerians. _2d Exception._—Visitors and attendants are liable to increase their ordinary chance of taking the prevalent distemper, by touching the body or clothes of the sick, when he labours under a disease marked by a palpable contagious poison. Though the poison cannot be diffused through the air, it may, and sometimes does, act by contact, which we call contactual or immediate contagion. That, of course, can operate in those diseases only in which a palpable poison is eliminated. Those diseases are in this country chiefly small-pox, chicken-pox; the plague, if it can now be said to be a disease of this country; the itch; and, as is commonly believed, measles, scarlet fever, &c. &c. Though the propagation of these diseases may take place from contact with their peculiar contagious matters, we are disposed to think, that, at least with most of them, especially the latter, the cases which occur in that way are very few. It is sometimes difficult to produce disease, even when the skin is cut, and the matter is then introduced. That step sometimes fails in respect to cow-pox matter, even when fresh; and small-pox matter we have known to be in contact with the tips of the finger for a minute or so, in innumerable cases, as in feeling the pulse, and no disease has followed. Women affected with small-pox bear healthy children. Almost the only diseases which we are disposed to think are propagated by contact with the person or clothes of the sick, are small-pox, chicken-pox, scabies, plague, &c. They all possess palpable matters in abundance. Many instances are known to us, where children have got small-pox, and of grown-up people who have got itch, from sleeping with those sick of these distempers, and thus coming in contact with them closely, and for some time; and where they have not been seized with them, when only breathing the same atmosphere used by those sick. Thus visitors and attendants may get disease by contact with palpable contagious matter, that is, by contactual contagion, and by touching clothes impregnated with the same, that is, by fomitic contagion, which they would not have taken, had they merely been respiring the air used by the patients.