FEVERS. 529 



alone. I have added 6 circiter,"* for though the interval is ge- 

 nerally forty-eight hours, nature is by no means so exact or 

 uniform in this particular, the fits coming frequently a little 

 sooner or later than that period. 



" Of the Tertian there is but one species ; all the other 

 subdivisions are merely varieties, and I have been even doubtful 

 in what manner to lay out these ; I proceed therefore by sub- 

 divisions, which I find generally useful. The difficulties in 

 tracing the varieties arise from this, that the forms of nature 

 are various, and these varieties are constantly interchanging 

 with one another ; therefore we do not pretend to establish any 

 thing as universal but only as more general. 



" I divide each genus of intermittent fevers into two heads, 

 those admitting of a perfect intermission (interposita apyrexia) ; 

 and those which admit of a remission only (interposita remissione 

 tantum.) 



" I. Tertians with a perfect intermission, vary in five different 

 ways ; 1. Paroxysmi duratione ; 2. Paroxysmorum recursu ; 

 3. Symptomatis ; 4. Aliis morbis complicatae ; 5. Ratione prin- 

 cipii. 



" 1. By the duration of its several paroxysms (paroxysmi 

 duratione) ; the more universal form of tertians is that which I 

 have set down first, ' Tertiana paroxysmis haud ultra horas 

 duodecim extensis.' The fit always lasts more than six hours ; 

 and where it has an intermission, it is finished in ten, though 

 sometimes it extends to nearly twelve hours. As this is the most 

 usual form, it has been called Tertiana legitima. When the 

 paroxysms are longer, the fever is called spurious : hence the 

 division into the 4 legitima,' and the ' spuria sive notha ;' the 

 latter of which is defined fi Tertiana paroxysmis ultra horas duo- 

 decim extensis. 1 These tertians never go the length of eighteen 

 hours, or if the paroxysms are longer, the fever becomes actual- 

 ly a remittent. 



" 2. By the recurrence of the paroxysms being more frequent 

 (paroxysmorum recursu) ; and of this there are again several 

 varieties. Thejirst : ( Tertiana quotidie revertens, paroxysmis 

 inaequalibus, alternis similibus ;** a Tertian which has a fit every 

 day, those on the two successive days being unequal, but 

 these on the alternate ones equal ; the double tertian of Sau- 



