_4th Exception._—That of the attendants in Fever Institutions. It has often been remarked, that in some fever institutions the nurses and medical clerks resident in the house, are attacked with fever in a much greater ratio than holds with the population around. The difference has been seen on some occasions to be very great, and from information collected on the subject, we are disposed to think, on some occasions, and in reference to some institutions at least, that the statement is correct. That fact has been attributed to atmospheric contagion; and we shall proceed to inquire if it is not more likely that it is dependent on other circumstances which are operating, and that are known to be adequate for the effect observed. The history of the Royal Infirmary of Edinburgh, and of Queensberry House, an institution for the reception of fever patients, shews that on some occasions almost all the clerks and nurses waiting upon those affected with fever, have been seized with it also. And it would appear to be owing to some agency peculiar to fever patients or their wards; for in regard to the first-mentioned institution, it is ascertained that it is with those attendants only, who wait upon those patients, that the greater amount of sickness is experienced. Those attendants exclusively occupied in the surgical wards being attacked in no greater proportion than those unconnected with the institution. This is certainly an important fact, and one on which the advocates of atmospheric contagion are wont to place no small weight. Did that principle exist, there is perhaps no fact in the whole history of medicine, on which we would place more reliance in proving its operation, for it is self-evident that nothing relating to the general unwholesomeness of the institution can be entitled to much activity in this case, for any insalubrious tendency of its situation, of the soil on which it stands, or emanations therefrom, and of the general economy and discipline, cannot be confined in their operation to one apartment or ward, cannot possibly be experienced in the fever wards only. But an occurrence of this kind is apt to be too readily received and made the ground of many inferences. In itself it certainly is a strong, a cogent fact, and such as naturally leads the mind to believe, that, as some very potent agency is at work, it may be that of atmospheric contagion, which in alleged activity is surpassed by none. Before proceeding to explain the occurrence, on principles very different from atmospheric contagion, it is right to say that it is such as does not occur in connection with all such institutions; and that, if the case which has been stated, proves it is likely such a principle as contagion is present in these institutions, that others of a directly opposite nature, and as much to the purpose, can be produced to shew, granting the possibility, that it is not present in other institutions, much larger.