Page:Transactions of the Royal Society of Tropical Medicine and Hygiene, volume 1.djvu/192

164 in an acute filarial abscess as to leave no trace in a few days.

In lymphangitis, again, it is difficult to understand the mechanism. Dr. Low {Journal of Tropical Medicine, August 15, 1902) says " the onset of an attack of filarial lymphangitis may be provoked, especially in old eases of filarial disease, by any trivial scratch or abrasion, etc." But that is surely a very frequent history of any attack of lymphangitis; it simply means that a source of streptococcal infection had been provided, and unless it is suggested that the presence of F. nocturna produces some change in the human body, say, by altering the opsonic index, so as to predispose to streptococcal infection, it is difficult to understand what the influence of the filaria is. This is a point which is worthy of investigation. I must confess, then, to a feeling that the proof of the connection of lymphangitis, abscess, and filariasis is not of a very convincing description.

2. The second suggestion is that elephantiasis and chyluria are due to impaction of the parent worm in some part of the lymphatic system—that there is a mechanical obstruction. So far as elephantiasis is concerned, I do not think that this is now seriously urged. It is certainly difficult to understand how a single live worm of the calibre of the F. bancrofti could produce such total obstruction as to lead to almost complete stasis of the lymph stream. I can understand a dead worm producing a blocking in the main lymphatic trunk in the following way: If we watch a piece of thread floating along a sluggish stream, it will remain extended until the anterior end meets some obstacle; the pressure of the water makes it fold on itself, and this process may be repeated until the thread is twisted up. And so with a dead filaria. Losing the power of anchoring itself, which it must have, it drifts along the lymph stream, in some main trunk, until it meets with some narrowing