Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1.djvu/204

 elephantiasis, but if one went behind the scenes it would be found that it was common in both races. Leaving the geographical question out of consideration, he desired to pass to one clear point the author had made, namely, that we do not know the exact mechanism and action of F. hancrofti in producing elephantiasis and other diseases. Unfortunately, post-mortems were difficult to get, especially at the stage when one would most like them — viz., after the first attack of filarial lymphangitis — for by careful inspection it might then be possible to ascertain where the parent filar ia was lying and in what way it caused obstruction. But, speaking pathologically, it was exceed- ingly difficult to explain how the filaria came to block the lymphatics. The author, and those who denied the existence of the filaria as a cause of elephantiasis, adduced cases of the disease seen at home. He had seen several such instances himself. The first case of elephantiasis he had ever seen was in a woman who lived in Vienna, and who had suffered from chronic eczema. Another was that of a city watchmaker treated at the Tropical School, who had never been out of London ; and the author quoted a case of double elephantiasis of the legs seen in London. He did not see that these cases invalidated the theory that the filaria was the chief cause of similar conditions in the Tropics. It was agreed that gonorrhoea caused 90 per cent, of all cases of stricture of the urethra ; but, on the other hand, such a condition might be due to traumatism and other causes. In the same way stenosis of the trachea might be caused by aneurism or other lesions ; and it stood to reason that it was the same with filarial infection. Any condition which blocked the thoracic duct, such as a tumour pressing on it, might easily produce the necessary stenosis. And regarding the distribution of elephantiasis, it was manifest that the filaria was at least one of the causes which produced the condition. For example, elephantiasis