The parasites which may cause hemorrhage in the substance of the kidney are the Bilharzia hæmatobia, the Filaria sanguinis hominis, the Strongylus gigas, and possibly common intestinal worms which may reach the kidney through fistulous openings. The first is a thread-like worm three or four lines in length, which was discovered by Bilharz, and infests the small vessels of the mucous and submucous tissue of the veins of the intestinal tract, the pelvis of the kidney, ureter, bladder, and more rarely of the kidney itself. It is very frequent in Egypt, where Griesinger found it 117 times in 363 autopsies; also in South Africa (Cape of Good Hope), where it gives rise to an endemic hæmaturia. It has been studied by Bilharz, John Harley, and William Roberts. The Filaria sanguinis hominis is a long, narrow microscopic worm, not wider than a red blood-disc, and one seventy-fifth of an inch long, which infests the blood. Hemorrhages result from its accumulation in the vessels, causing rupture. The cases which have been studied occurred mostly in India, China, and Australia. The Strongylus gigas is a large worm, resembling the ordinary lumbricoid, but larger, the male being from ten to twelve inches long and one-fourth of an inch wide, while the female is sometimes more than a yard in length. It infests the kidneys and urinary passages of certain lower animals (the dog, wolf, horse, ox, etc.), but rarely those of man. {107} Malarial Hæmaturia and Hæmoglobinuria. SYNONYMS.--Intermittent hæmaturia; Paroxysmal hæmaturia; Malarial yellow fever; Swamp yellow fever; Paroxysmal congestive hepatic hæmaturia (Harley). Perhaps the most important form of hæmaturia and hæmoglobinuria resulting from general causes is that due to malarial poisoning. I prefer the term malarial to intermittent or paroxysmal, not only because it more precisely indicates the cause of the condition, but also because the condition itself is by no means always intermittent, sometimes continuing without interruption until checked by appropriate treatment; and I have known it to continue uninterruptedly for a year, in spite of all treatment. The first complete report of an undoubted instance of this affection appears to have been published by Dressler in 1854,[2] although incomplete and uncertain cases were reported prior to this date--one as early as 1832 by Elliotson.[3] G. Troup Maxwell of Ocala, Florida, writes me, in 1883, that he first observed cases in Florida thirty years ago, and published an article on the disease in the _Oglethorpe Medical Journal_, Savannah, Ga., July, 1860. George Harley[4] early contributed to our accurate knowledge of the subject in 1865, and since then numerous papers and reports of cases have appeared in English and American journals, the southern part of the United States being a fertile scene of the affection, while it is by no means rare in the Middle States.