FEVERS. 549 



which the temperature applied produces a sensation of cold ; and 

 this, therefore, as depending entirely on the relative power of 

 cold, will be in proportion to the change of temperature that 

 takes place. 



It appears to me probable that every change of temperature, 

 from a higher to a lower degree, will prove more or less stimu- 

 lant ; excepting when the cold applied is so intense as imme- 

 diately to extinguish the vital principle in the part. 



3. Beside the sedative and stimulant powers of cold, it is 

 manifestly also a powerful astringent, causing a contraction of 

 the vessels on the surface of the body, and thereby producing a 

 paleness of the skin and a suppression of perspiration ; and it 

 seems to have similar effects when applied to internal parts. It 

 is likewise probable, that this constriction, as it takes place es- 

 pecially in consequence of the sensibility of the parts to which 

 the cold is applied, will, in some measure, be communicated 

 to other parts of the body ; and that thereby the applica- 

 tion of cold proves a tonic power with respect to the whole sys- 

 tem. 



These effects of tonic and astringent power seem to take place 

 both from the absolute and relative power of cold ; and there- 

 fore every application of it which gives a sensation of cold, is, in 

 its first effect, both astringent and stimulant, though the former 

 may be often prevented from being either considerable or per- 

 manent, when the latter immediately takes place. 



XCI. It will be obvious, that these several effects of cold 

 cannot all take place at the same time, but may, in succession, 

 be variously combined. The stimulant power taking place ob- 

 viates the effects, at least the permanency of the effects, that 

 might otherwise have arisen from the sedative power. That the 

 same stimulant power prevents these from the astringent, I have 

 said above ; but the stimulant and tonic powers of cold are com- 

 monly, perhaps always, conjoined.' 



XCII. These general effects of cold now pointed out are 

 sometimes salutary, and frequently morbid ; but it is the latter 

 only I am to consider here, and they seem to be chiefly the fol- 

 lowing. 



1. A general inflammatory disposition of the system, which is 

 commonly accompanied with rheumatism or other phlegmasise. 



