Ixxviii. PRESIDENT'S ADDRESS. 



very technical, but it seems not improbable that out of it may, in 

 time, come our next great advance in the knowledge of organic 

 evolution. It seems hardly possible that natural selection can 

 ever be relegated to the position of an exploded theory, but it 

 may have new truths grafted upon it, arising out of the investiga- 

 tions now so closely pursued. The existence of a problematical 

 animal from South Africa, in the region of the Okapi, resembling 

 a huge black pig, is confirmed, and it has been named 

 Hylochoerus meinertzhageni. A new vole, Microtus orcadensis, has 

 also been described from our own small island. Our knowledge 

 of the evolution of the horse has been much increased by the 

 finding of fresh remains in North America, and it has been 

 shown that the age of fishes of the cod tribe, and perhaps 

 others, can be deduced from the rings of growth on their scales, 

 much as that of cows from the rings on their horns. It has been 

 shown by breeding that in a South African butterfly (Papilio 

 Dardanus) there are three distinct forms of the female, each of 

 which mimics a different Danaine species. It is with great 

 satisfaction that I learn that the Chartley cattle, which have 

 been kept continuously in Chartley Park, Staffordshire, for about 

 650 years, have been bought by the Duke of Bedford, and will 

 doubtless be carefully preserved intact, though it is sad that they 

 should be removed from their ancient home. That queer little 

 New Zealand bird, the Apteryx, is to be protected ; and it has 

 been demonstrated that terrible scourge, sleeping sickness, is 

 caused by a Protozoan organism, Trypanosoma gambiense, con- 

 veyed by a species of Tsetse-fly. Finally, to show how little 

 new there is under the sun, it has been stated by the Governor of 

 Ceylon that native medical books of the sixth century described 

 67 varieties of mosquitoes and 424 kinds of malarial fever 

 caused by those insects a fact which the world thought it had 

 only discovered in the last few years. To show the efficacy of 

 modern anti-mosquito measures, I may instance two places in 

 Malay, where in 1902, after these had been carried out for a year, 

 the cases diminished to about one-sixth of those in 1901. After 

 three years they only amounted to about one-eighteenth. 



