FEVERS. 531 



the forenoon of that day, which remits towards the evening, 

 when there is a new exacerbation. Or you may take it very 

 distinctly from Cleghorn ; there is a Tertian to be met with, 

 he says, in which there are three different periods, three fits, 

 and as many intervals. Here you will observe that what Cleg- 

 horn calls a period, I call an interval, and what he calls an in- 

 terval, I call a remission. As I have explained it, this form 

 of Tertian fever returns every day, but with a remission that is 

 more considerable on the one day, and hardly to be noticed on 

 the other. This is the Hemitritaeus of Celsus, and the Semi- 

 tertiana of Cleghorn. It is true I have the testimony of most 

 authors, that what has been called the Semitertian is a remittent 

 fever only ; but there is something undetermined in that matter, 

 which is not very easily avoided, for there are truly no bounds 

 or limits to be set to these forms, as they are constantly running 

 from a true tertian, consisting of a fit of eight or ten hours, to a 

 spurious tertian whose fit extends to eighteen hours, then to a 

 double tertian having a fit every day, then to two fits in one 

 day, then to one fit in one day, and to two in another ; then truly 

 and entirely to a remittent. 



" After these observations, you must not be surprised at my 

 mentioning the varieties so accurately here. Whether it is of 

 importance to attend to such, I cannot say ; but it would be 

 dangerous to say that these varieties are of no importance. 

 We must first take the facts as they are, and even the superflu- 

 ous ones, least we should miss any that are of consequence. It 

 were to be wished that we had the species of diseases in a noso- 

 logical method with some accuracy ; I am aiming at it, but it 

 is a task I am not able to perform. It requires more experience 

 and actual practice than I have had, and also an immense eru- 

 dition in looking into the facts, which is a circumstance that my 

 own parts, and my own library, or any other I can be supplied 

 with, are not sufficient for, so that I might proceed on my own 

 bottom. Sauvages is the only person who has attempted this ; 

 but what a mass of confusion there is in this part of his work ! 

 It is of importance that I point out his mistakes, and endeav- 

 our to correct them. 



" 3. By their symptoms ; the principal varieties of tertians 



