Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1.djvu/32

8 must have chapters on spirillosis, seeing that the term "relapsing fever" which Murchison and others used, and which Carter also used in his studies in India, covers not one but a number of infections, spread probably by a corresponding number of previously unsuspected ticks or other blood-suckers.

Then the tropical pathologist must take cognisance of a number of diseases of the lower animals, important in themselves, but more important in their bearing as illustrating principles applicable to human pathology especially tropical pathology. The study of the arthropod blood-suckers and the correlated diseases has grown to be so vast a subject that for its proper appreciation special studies have to be made and its teaching relegated to special men. In Davidson's day a single culex was all that we had to bother ourselves about; but nowadays we have to know something about some 600 species of mosquitoes; and so in a less degree with ticks, tsetse flies, and several other though less important blood-suckers. Truly the burden of the student of tropical medicine has become a heavy one.

I might enumerate many other discoveries and changes in our special branch. Those I have alluded to suffice to show that within the last thirteen or fourteen years the progress in tropical medicine has been phenomenal. If we are justified in looking upon the recent past as an earnest of what will take place in the near future, my successor thirteen or fourteen years hence, when he sums up the additions that will have been made to our subject by that time, will have, perhaps not a more difficult task, but certainly a longer one.

Not only has recent discovery widened our horizon, but many additional workers are now in the field, and hitherto untrodden departments of natural science having a bearing on tropical pathology have been opened by the tropical