FEVERS. 515 



can judge of the resistance of the morbid state of fever : and 

 with respect to this spasm, I observe, that either the cause ex- 

 citing it may be different in different cases, or, though the 

 cause should be the same in different persons, the different de- 

 gree of irritability in each may give occasion to a greater or 

 lesser degree of spasm ; and, therefore, the reaction in fever be- 

 ing given, the continuance of the hot stage, and of the whole 

 paroxysm, may be longer or shorter, according to the degree of 

 spasm that has been formed. 



LXII. One cause of the obstinacy of spasm in fevers may 

 be clearly perceived. In inflammatory diseases there is a dia- 

 thesis phlogistica prevailing in the body, and this diathesis we 

 suppose to consist in an increased tone of the whole arterial 

 system. When, therefore, this diathesis accompanies fever, as 

 it sometimes does, it may be supposed to give occasion to the 

 febrile spasms being formed more strongly, and thereby to pro- 

 duce more protracted paroxysms. Accordingly we find, that 

 all inflammatory fevers are of the continued kind ; and that all 

 the causes of the diathesis phlogistica have a tendency to change 

 intermittent into continued fevers. Continued fevers, then, be- 

 ing often attended with the diathesis phlogistica, we conclude, 

 that, in many cases, this is the cause of their continued form. 



LXIII. In many fevers, however, there is no evidence of 

 any diathesis phlogistica being present, nor of any other cause 

 of more considerable spasm ; and, in such cases, therefore, we 

 must impute the protraction of paroxysms, and the continued 

 form of the fever, to the weakness of the reaction. That this 

 cause takes place we conclude from hence, that, in many cases 

 of fever, wherein the separate paroxysms are the longest pro- 

 tracted, and the most difficultly observed, we find the most con- 

 siderable symptoms of a general debility ; and therefore we in- 

 fer, that in such cases the protracted paroxysms, and continued 

 form, depend upon a weaker reaction ; owing either to the causes 

 of debility applied having been of a more powerful kind, or from 

 circumstances of the patient's constitution favouring their ope- 

 ration. 



LXIV. Upon these principles, we make a step towards ex- 

 plaining in general, with some probability, the difference of 

 fevers ; but we must own, that there is much doubt and difficulty 



