AND ANIMAL LIFE. 399 



CCCCLXXIV. It is seldom that a series of 

 propositions is altogether true or false ; and the 

 correctness of this observation is obvious, when 

 applied to the different theories concerning sym- 

 pathy. But if these had been capable of demonstra- 

 tion, or had immediately enlightened our pro- 

 fessional views, our reasonings would have been 

 less confused and indistinct. The great objec- 

 tion to the prevalent opinions with respect to 

 the laws of sympathy is, that they are either 

 gratuitous, or suggest little improvement in 

 practice. 



CCCCLXXV. It is not, on all occasions, 

 easy to detect error, and, when detected, it is 

 sometimes more difficult to supply its place with 

 truth. But, in medicine, the exposure of error, 

 sooner or later, leads to the establishment of 

 truth, or gives rise to principles that are more or 

 less salutary in their influence. In this chapter 

 I shall attempt to expose many important errors 

 either committed or supported by physiologists 

 of eminence ; and, while I liberally bring for- 

 ward the mistakes of others, I shall humbly pro- 

 pose opinions that appear to me better calculated 

 to solve the most essential phenomena of sym- 

 pathy, and which also appear to have a closer 

 connection with the indications of practice. 



CCCCLXXVI. Sympathy, however produced 

 by the different states of the body, I have di- 

 vided into the four following classes : 



