Page:The healing art in its historic and prophetic aspects - the Harveian oration delivered before the Royal College of Physicians, Oct. 19, 1885 (IA b21908199).pdf/31

 of certainty and truth, dependent on the essentially correct method by which the facts have been determined. processes.

Concurrently with the growth and diffusion of a scien- Morbid tific knowledge of the cansation of disease, and of its structural manifestations, there has arisen a better under- standing of morbid processes. The condition of inflamma- tion, which has been recognised from the earliest times, and has probably given rise to more discussion than any other subject in pathology, is now regarded in a manner which, whilst it admittedly leaves much to be discovered, is at least in harmony with our knowledge of the functions of normal nutrition. The pathology of Fever also, though not yet complete, may be said to have been scientifically studied only during the last fifty years. The systematic use of the clinical thermometer, the application of chem- ical testing to the secretions, and the improvements in the methods of bedside investigation generally, have revealed to us a vast number of facts which were unknown to observers at the beginning of the century.

Another factor of the greatest importance, both in relation to normal function and to disease, is the direct influence exercised by the nervous system on the tissue metabolism. We have no clear knowledge how this in- fluence is exercised, but the existence of some control is certain; and it is curious to notice how older notions of neural pathology recur in the more accurately defined con- ceptions of to-day. The comprehension of the part played by the blood in disease is also an advance which has been eminently fruitful in results, and which differs widely from the doctrine that at one time attributed every malady to some vitiated condition of the circulating fluid.

But nothing will bring the conviction of recent pro- Parasitic gress more completely home to our minds than a brief re- pathology. trospect of parasitic pathology during the last forty or fifty years. How great a step, though it looked but small at the