ON NOSOLOGY. 447 



show you how far they have fallen short of establishing such 

 characters. Within these hundred years, neglecting the study 

 of pathognomonics, we have thought of another measure ; we 

 have aimed at what we thought somewhat more complete, at 

 what we call a history of diseases, that is, the enumeration of the 

 whole of the symptoms that at any time accompany a disease, 

 collected under the title we employ ; a very useful work, to be 

 sure, nothing is more so ; but unluckily it happens that as yet 

 we have very few good descriptions or histories of diseases, and, 

 what is worse, the best descriptions do not answer our purpose ; 

 they contain a great deal of superfluous matter ; they assume 

 a certain title of a genus or species, and enumerate every single 

 symptom which, at any time or upon any occasion, has appeared 

 to accompany that disease, but they have taken no proper pains 

 to distinguish between what are the essential and what the 

 accidental symptoms, between the simple and the complicated 

 ones. 



This is a state of physic that requires very much to be 

 amended ; and this can be done in no other way but by the 

 application of methodical Nosology. 



If Nosology could be rendered tolerably perfect, nobody would 

 doubt of what I have been saying ; but several have refused to 

 admit that this is possible, and have objected to it upon different 

 considerations. The first and most considerable is this, that at 

 present the distinction of diseases lies in so much confusion, 

 that Nosology must certainly be difficult; and some carry it 

 so far as to assert that the attempt is impossible. But cer- 

 tainly this is going a great deal too far. I acknowledge very 

 readily, that many difficulties occur in methodical Nosology, 

 and the difficulties are sometimes such as I cannot pretend 

 to surmount; but this is not universal; if it were so, what would 

 be the consequence ? it would make the study of physic abso- 

 lutely impossible, for if we cannot arrive at some distinction of 

 diseases, we must act at random ; nay, this is as much as to say, 

 that there are greater difficulties in our way in ascertaining facts 

 than all that have been urged against false theories. But if on 

 the contrary, we can distinguish diseases, surely we can likewise 

 say in what manner we do distinguish them. Now Nosology 

 only tells you in what manner any person does distinguish dis- 



