640 PRACTICE OF PHYSIC. 



stood. But it is certainly allowable to inquire into this matter ; 

 and I apprehend it may be explained. 



CCXIV. To this purpose it is to be remarked, that as, in 

 many cases, the effects of the bark are perceived soon after its 

 being taken into the stomach, and before it can possibly be con- 

 veyed to the mass of blood, we may conclude, that its effects do 

 not arise from its operating on the fluids ; and must, therefore, 

 depend upon its operating on the nerves of the stomach, and 

 being thereby communicated to the rest of the nervous system. 

 This operation seems to be a tonic power, the bark being a 

 remedy in many cases of debility, particularly in gangrene : and, 

 as the recurrence of the paroxysms of intermittent fevers de- 

 pends upon a recurrence of atony (XXXV and XXXVI.), 

 so probably the bark, by its tonic power, prevents the recurrence 

 of these paroxysms ; and this is greatly confirmed by observing, 

 that many other tonic medicines answer the same purpose. 



CCXV. If the operation of the bark may be thus explained, 

 from its possessing a tonic power, it is easy to perceive why it is 

 improper when a phlogistic diathesis prevails ; and, from the 

 same view, we can ascertain in what cases of continued fever it 

 may be admitted. These are either after considerable remis- 

 sions have appeared, when it may be employed to prevent the 

 return of exacerbations, on the same footing that it is used in in- 

 termittent fevers, or in the advanced state of fevers, when all 

 suspicion of an inflammatory state is removed, and a general de- 

 bility prevails in the system ; and its being then employed is 

 sufficiently agreeable to the present practice. 



When Intermittent fevers have changed into Remittents, 

 and these have become of a very continued form, or when 

 either this transition has been manifestly perceived, or, from the 

 place of the patient's habitation, from the season of the year, 

 and from the nature of the prevailing epidemic, there is reason 

 to conclude that a fever has arisen from the same-marsh effluvia 

 which produce intermittent or remittent fevers in their ordinary 

 form ; in such cases, fevers, however continued in their form 

 they may then seem to be, may still be considered as of the in- 

 termittent kind, and be treated by the bark in the same manner 

 that we have shown may be done in remittent fevers of little 

 distinct remission. M. M. 



