Smith & Thomas Southwood 
A Treatise on Fever [PDF ebook] 

Excerpt from Preface:
The following Work is wholly of a practical nature: its object is to ascertain the real phenomena of Fever, and the most safe and effectual treatment of the disease. It was found impossible to include in this volume some researches of a statistical nature which it was at first intended to incorporate in the work.
On looking over the account which has been given of the phenomena, I find that, by an oversight, I have omitted to make any mention of the peculiar odour which belongs to a fever-patient. It is so characteristic that a person, familiar with the disease, might in many cases be able to pronounce, merely from the odour of the effluvia that arises from the body, whether the disease were fever.