ERUPTIVE FEVERS. 147 



notice, what is not universal can hardly be taken as pathogno- 

 monically characteristic. 



" Secondly, The determined duration of the fever, and the 

 fixed period of the eruption, also afford us a very good part of 

 our character; at least we find that both of these are very steady 

 and of surprising uniformity. In many of the genera, the 

 nicety of this part of the character goes so far, that whenever 

 it does not take place positively, it gives doubt whether there is 

 any thing like specific contagion, whether there is any proper 

 Exanthema. 



" Thirdly, I have to observe, that the effects of the conta- 

 gion, where it is known, appear different with regard to the 

 place to which its operation is determined. It does not at first, 

 but always at length, operate more or less topically. The de- 

 termination may be said to be of three kinds : The first is 

 that to the skin, which is the most common and universal, and 

 which almost necessarily belongs to the idea of an Exanthema. 

 The second is that to the mucous glands, more remarkably to 

 those of the fauces and bronchia?, but as I judge, also to those of 

 the intestines, producing diarrhoea. It is sufficiently evident, 

 that these are determinations of the contagion. We have what 

 may be called primary diseases, anginas and catarrhs, with these 

 determinations steadily and constantly : now these are very 

 commonly accompanied by some Exanthema. On the other 

 hand, some Exanthemata, which are also to be considered as in 

 the strictest sense primary diseases, are almost inseparable from 

 a determination to the fauces and bronchiae, and in many cases it 

 comes to be a question, which of these is to be considered as the 

 primary disease. Thus, I say, it might be doubted, whether the 

 Angina gangraenosa ought not to be considered as an Exanthe- 

 ma ; and whether the scarlet angina, when very universal and 

 common, may not be considered as strictly an exanthematous an- 

 gina. A third determination, to which we must attend, is that 

 to the lymphatic glands, producing buboes and parotides. When 

 these arise alone, without any exanthematic appearance, or in 

 diseases not commonly attended by such, there may be a ques r 

 tion whether they are to be considered as a species of exanthe- 

 ma ; but we are led to class them together, because they es- 

 pecially occur in diseases which arise from contagion, and are 



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