AND ANIMAL LIFE. 441 



sionally, great changes in the hygrometric condi- 

 tion of the atmosphere, in the degree of cold, and 

 also in the frequency and severity of the winds. 

 If these changes be sudden or extensive, the 

 blood will necessarily become internal rather than 

 external in its circulation, not from a regular di- 

 minution of those stimuli or excitants that main- 

 tained the former state, but from an abrupt sup~ 

 pression of them ; and as the organs on which the 

 blood is driven cannot instantaneously adapt them- 

 selves to this unusual quantity, their individual 

 functions are deranged. The mucous membrane 

 of the intestines in dysentery is invariably dis- 

 eased. It is not improbable, at this season, that 

 this membrane is more susceptible of the influ- 

 ence of those agents w r hose action I have endea- 

 voured to explain than at any other, from the 

 tendency which fruit, and indulgences of the sea- 

 sons, have to disorder its functions. If it be 

 granted, from this short and incomplete sketch 

 of the disease, that there is a state of congestion 

 either co-existent with, or subsequent to, the 

 operation of the exciting cause, it will then be 

 easy to understand why the exhibition of emetics 

 is beneficial. When these induce vomiting, either 

 at the commencement of the affection or when it 

 is fully formed, the effect is, that the sanguineous 

 fluid is more equally diffused throughout the sys- 

 tem, and as it is also better oxygenated, the in- 

 testines are not only relieved of that quantity of 



