III. Or the new disease, after having long acted on the organism, at length joins the old one that is dissimilar to it, and forms with it a complex disease, so that each of them occupies a particular locality in the organism, namely, the organs peculiarly adapted for it, and, as it were, only the place specially belonging to it, while it leaves the rest to the other disease that is dissimilar to it. Thus a syphilitic patient may become psoric, and vice versa. As two disease dissimilar to each other, they cannot remove, cannot cure one another. At first the venereal symptoms are kept in abeyance and suspended when the psoric eruption begins to appear; in course of time, however (as the syphilis is at least as strong as the psora), the two join together,1 that is, each involves those parts of the organism only which are most adapted for it, and the patient is thereby rendered more diseased and more difficult to cure.
When two dissimilar acute infectious diseases meet, as, for example, smallpox and measles, the one usually suspends the other, as has been before observed; yet there have also been severe epidemics of this kind, where, in rare cases, two dissimilar acute diseases occurred simultaneously in one and the same body, and for a short time combined, as it were, with each other. During an epidemic, in which smallpox and measles were prevalent at the same time, among three hundred cases (in which these diseases avoided or suspended one another, and measles attacked patients twenty days after the smallpox broke out, the smallpox, however, from seventeen to eighteen days after the appearance of the measles, so that the first disease had previously completed its regular course) there was yet one single case in which P. Russell2 met with both these dissimilar diseases in one person at the same time. Rainey3 witnessed the simultaneous occurrence of smallpox and measles in two girls. J. Maurice4, in his whole practice, only observed two such cases. Similar cases are to be found in Ettmuller’s5 works, and in the writings of a few others.
Zencker6 saw cow-pox run its regular course along with measles and along with purpura.
The cow-pox went on its course undisturbed during a mercurial treatment for syphilis, as Jenner saw.
1 From careful experiments and cures of complex diseases of this kind, I am now firmly convinced that no real amalgamation of the two takes place, but that in such cases the one exists in the organism besides the other only, each in pairs that are adapted for it, and their cure will be completely effected by a judicious alternation of the best mercurial preparation, with the remedies specific for the psora, each given in the most suitable dose and form.
2 Vide Transactions of a Society for the Improvement of Med. and Chir. Knowledge, ii.
3 In Edinb. Med and Phys. Journ., 1805.
4 In Med. and Phys. Journ., 1805.
5 Opera, ii, p.i, cap. 10.
6 In hufeland’s Journal, xvii.