the scrotum. (4) Elephantiasis of the leg sometimes supervenes on the surgical removal of a lymph scrotum. (5) Elephantiasis and lymphatic varix are essentially diseases of the lymphatics. (6) Filarial lymphatic varix and true elephantiasis are both accompanied by the same type of recurring lymphangitis. (7) As filarial lymphatic varix is practically proved to be caused by the filaria, the inference that the elephantiasis of warm climates, with rare exceptions —the disease with which the former is so often associated and has so many affinities— is attributable to the same cause, appears to be warranted.
Explanation of the absence of microfilariœ in the blood in elephantiasis.— If the filaria be the cause of tropical elephantiasis, how account for the absence of filaria larvæ in the blood, as is the case in the vast majority of instances of this disease? The answer is: Either the disease-producing filariæ have died; or the lymphatics draining the affected area are so effectually obstructed by the filaria, its products, or its effects, that any microfilarise they may contain, or may have contained, cannot pass along these vessels to enter the circulation. Adult filarise of both sexes in large numbers may be found in enlarged fibrosed lymphatic glands— epitrochlear, for example— without the presence of the corresponding microfilariæ in the blood- stream.
We have already said that in filarial lymphatic varix the parasites which produced the disease may die, particularly during attacks of lymphangitis; we have also seen that they may become cretified and may be found in large numbers in this condition or alive in the glands and lymphatic trunks, where, as Bahr has shown, they give rise to giant-cell formation and-fibrotic changes of an obstructive nature. (Figs. 112, 113.) I do not think, however, that this is the entire explanation of the origin of elephantiasis.
Lymph stasis produced by filaria ova.— I have twice in filariasis found ova of the filaria in lymph; once in the lymph from a lymph scrotum, once in lymph procured by aspirating a varicose groin gland. Therefore, at times, the filaria may produce ova
