In treating upon this subject, I shall
I. Consider the proper subjects, and seasons for inoculation.
II. I shall describe the method of communicating the disease.
III. I shall consider the method of preparing the body for the small-pox.
IV. I shall mention the treatment proper during the eruptive fever. And,
V. Point out a few cautions that are necessary after the disease is over.
I. Formerly there were great difficulties in the choice of subjects for inoculation. But experience teaches us, that it may be practised in every stage of life, and in almost every condition of the human body. In infancy, the periods before and after dentition are to be preferred. But we seldom see any great inconveniences from submitting to the general necessity of inoculating children between the ages of three months, and two years. Indeed we often see children cut three or four teeth during the preparation and eruptive fever, without the least addition being made to any of the troublesome symptoms which accompany the small-pox. There is one inconvenience attending the choice of the first months of infancy for inoculating, and that is, the matter often fails of producing the disease in such young subjects. I have frequently failed in two or three attempts to communicate it to children under four months old, with the same matter that has succeeded in a dozen other patients, inoculated at the same time. When the inoculation succeeds in such tender subjects, they generally have less fever, and fewer pustules, than are common in any future period of life.
Although a physician would prefer a patient in good health to any other as a subject for inoculation, yet cases often occur in which it is necessary to communicate the small-pox while the body is affected with some other disease. I can with pleasure inform you, that the small-pox is rendered so perfectly safe by inoculation, that there are few chronic diseases which should be considered as obstacles in the way of it. I have inoculated patients labouring under a tertian fever, obstructed viscera, the hooping cough, the hypochondriasis, the asthma, the itch, and other cutaneous diseases, and even pregnant women, with the same, and, in some instances, with greater success, than persons in perfect health. Doctor Cullen informs us, that he has seen inoculation succeed in scrophulous patients. A physician in Jamaica informed me, that he had inoculated negroes with success in the worst stage of the yaws. To these facts I must add one more extraordinary than any that has been yet mentioned: Doctor Brown, my late colleague in the care of the military hospitals, informed me, that he had seen inoculation succeed in patients who were seized, after the infection was communicated, with the hospital fever. The preparation of the body should be accommodated to the disease which affects it. Some physicians have thought the small-pox, received in this way, was a remedy for other diseases; but my experience has not confirmed this opinion: on the contrary, I am inclined to think that no other change is produced by inoculation, than by the regimen and medicines that are used to prepare the body for the small-pox. Nor does the small-pox, during its continuance, afford any security against the attacks of other diseases. I have seen the most alarming complication of the small-pox and measles taken in succession to each other, in the same person.
The seasons commonly preferred for inoculation, in this country, are the spring and fall. It may be practised with equal safety in the winter, a due regard being had to the temperature of the air in the preparation of the body.