Organon §40
Sometimes two diseases of equal strength form a complicated disease in which each of the two occupies a different part of the body.
iii. It can also happen that the new disease, after impinging for a long time on the organism, joins the old one that is dissimilar to it, and they form a complicated disease. Each disease takes in its own region in the organism, that is, it takes the organs especially appropriate for it. As it were, it takes only the peculiar place that is proper to it, leaving the rest of the organism to the dissimilar disease.
Venereal disease complicated with psora
1. A venereal patient may become psoric and vice versa but the two dissimilar diseases cannot lift one another; they cannot cure one another. When the itch diathesis eruption begins to appear in a person with venereal disease, the venereal symptoms keep silent and become suspended. But in time (since the venereal disease is at least as strong as the itch diathesis) the two associate themselves with one another, 91 that is, each takes for itself only those parts of the organism that are appropriate for it. The patient is thereby rendered more diseased and more difficult to cure.
Smallpox complicated with measles
2. When two dissimilar acute infectious diseases meet (such as smallpox and measles), one usually suspends the other, as has been adduced [§38]. There have, however, been rare instances in violent epidemics where two dissimilar acute diseases occurred simultaneously in one and the same body and so, as it were, complicated themselves for a short time. [For example, there are several accounts of smallpox and measles occurring at the same time in one person.] In an epidemic where smallpox and measles reigned at the same time, there were close to 300 cases in which these diseases avoided or suspended one another. The measles would only break out twenty days after a smallpox outbreak befell a person, and the smallpox would only break out 17 to 18 days after a measles outbreak would befall someone such that the earlier disease would first fully run its course. Nevertheless, Russel came across a case in which both dissimilar diseases were in the same person at the same time. 92 Rainey saw the simultaneous occurrence of smallpox and measles in two girls. 93 Maurice states that he observed only two such cases in his entire practice. 94 Similar cases are found in Ettmьller 95 and in the writings of a few others.
Cowpox complicated with measles and miliary fever
3. Zencker saw cowpox retain its regular course along with measles and also with miliary fever. 96
Cowpox complicated with syphilis treatment
4. A case of cowpox went on its way undisturbed during a mercurial treatment for syphilis, according to Jenner.
Comment
91 From exact experiments and cures of complicated diseases of this kind, I am now firmly persuaded that no real fusion of the two diseases takes place. The two diseases exist beside one another in the organism, each in the parts that are suitable for it. The cure of the diseases will be completely produced by the timely alternation of the best antisyphilitic means with the best means for curing the itch diathesis [i.e. , the best antipsoric medicine], each prepared in the most appropriate way and given in the most appropriate dose.
92 P. Russel, in Transactions of a Society for the Improvement of Med. and Chir. Knowledge, vol II.
93 Rainey, in Medical Commentaries of Edinburgh, vol. III, p. 480.
94 J. Maurice, Med. and Phys. Journ., 1805.
95 Ettmьller, Opera, vol. II, pt. I, chap. 10.
96 Zencker, in Hufeland's Journal der practischen Arzneikunde [Journal of Practical Medicine], vol. XVII.