293 



pronounce that a certain secondary disease will succeed to the 

 primary, and that the latter will then cease. We more frequently 

 expect the cessation of a primary disease, when the symptoms of a 

 secondary one, of the tendency of which we have had experience, do 

 actually appear, than we anticipate a substitution of disease, while 

 the existing symptoms occupy exclusively the primary seat. There 

 is, however, an exception to this remark, when the same secondary 

 has been substituted for the same primary disease, in one or more 

 instances. 



14. It is desirable on this subject that the collective experience 

 of individuals should be possessed, in order that our reasonings may 

 receive the advantage which must be derived from a correct estimate 

 of the frequency and peculiarities of substituted disease. My own 

 experience of these diseases is pretty extensive, and I have elsewhere 

 made some progress in an attempt at their classification; at least, I 

 have collected and arranged many detailed cases. In this place a 

 few only of the instances can be adverted to, as illustrative of the 

 cessation of one disease by the substitution of another. In this way, 



1. Chronic pain in the head may cease upon the occurrence of a 

 chronic diarhoea. 



2. Violent pain in the head, accompanied for a considerable time 

 by general derangement of the health, and particularly of the nervous 

 system, may be cured, to use a common term, by the formation of an 

 abscess in the back. 



3. Pain in the head, disorder of the nervous system, which has 

 proceeded to insanity of three weeks' duration, may all cease upon 

 the formation of a carbuncle in the back. 



4. Chronic plethora of the vessels of the head, producing vertigo, 

 lethargy, &c. requiring frequent depletion by cupping or by the 

 lancet, may cease, so as never again to require these artificial mea- 

 sures, upon the occurrence of a large incurable ulcer in the back. 



5. Insanity, which had existed a twelvemonth, ceases perhaps 

 under an enormous accumulation of fat. The formation of fat is of 

 all others the most frequent instance of substituted disease. It 

 cures habitual disorder, improves the condition of that which is 

 called a delicate constitution when it occurs. The formation of fat 

 tends to maintain health by defining a harmless seat of disease while 

 it lasts, and it is seldom spontaneously removed without the occur- 

 rence of a substituted disease in some less convenient seat. 



(J. Vertigo, alternating with asthma, may cease upon the for- 

 mation of an abscess of the foot; this abscess may produce a 

 troublesome wound, upon the healing of which apoplexy may take 

 place, followed by paraplegia and fatuity; to this may succeed 

 swelling of the legs with improved motion, and recovery of the 

 intellectual powers; to a cessation of the swelling of the legs may 

 succeed spasmodic breathing, which ceases again upon the return of 

 the swelling of the legs; this again ceasing, apoplexy and death 

 supervene. 



