Page:The Harveian oration, delivered before the Royal College of Physicians, Wednesday, June 27th, 1877 (IA b22314623).pdf/35

 instruments, will materially increase the value of thermometry, remains to be seen; but what we specially require is a means of determining the commencement of the incubative stage of febrile disease, so that we might be enabled to apply our remedies before the zymotic process has actually poisoned the entire system. The interval that elapses between the absorption of a germ and the actual manifestation of the complicated processes to which it gives rise is the period during which an antidotal or germicide agent would be most certain to effect the desired end. It suggests itself whether we are not likely to find, in a com- bination of the galvanometer and thermometer, the means of a further advance in this direction; and it seems to me that we must look to the galvanic test also for a solution of the problem, which is so often presented to the practitioner, how pain, which at present is only a subjective sign, can be rendered more objective; how we may estimate and measure this important symptom; how we can secure an instrument which, by anticipation, may be termed an odynometer.

The "tactus eruditus," upon which our pre- decessors justly laid stress, and which cannot now be dispensed with, is rendered more intelligible and receives a scientific basis in the explanations of the varying conditions of arterial tension afforded by the sphygmograph. It is one of those