In the middle of April I was seized with an attack of filariasis, a disorder caused by the sting of a certain kind of mosquito. During the day I had felt pain in the glands of the loins, which were swollen, without giving the matter any particular attention. As I am not in the habit of being ill, in fact, so far had prided myself on growing younger each year, this experience of suddenly becoming very weak and miserable was most unexpected. Vomiting set in, so I went immediately to bed, and slept soundly during the night and also most of the next day, when I found myself with an extremely high fever, much more severe than that which accompanies malaria, a pernicious form of which I once passed through on the west coast of Mexico. Until many months afterward I did not know the nature of my disorder, but resorted to the simple remedy always available--to stop eating, as Japanese soldiers are reported to do when wounded. On the fourth day the fever abated, after which improvement was rapid. Two days later my general condition was fair, although the lower part of the right leg, especially about the ankle, was red and swollen. I soon felt completely restored in spite of the fact that a painless swelling of the ankle remained. Two months later I had another attack, as sudden and unexpected as the first. This was ushered in by a chill exactly like that preceding malaria, but the fever that followed was less severe than on the former occasion, and in a few days I was well again. More than a year afterward hypodermic injections of sodium cacodylate were attempted with apparent success, though the swellings continued. Many months later an improvement in the condition of the leg was gradually brought about, to which perhaps a liberal consumption of oranges separate from meals, largely contributed. This affection is not common in Borneo. A native authority in Kasungan, on the Katingan River in South Borneo, himself a Kahayan, told me of a remedy by which he and eight other natives had been completely cured. It is a diffusion from three kinds of plants, applied externally, samples of which I took. On the last day of April we were able to continue our journey down the Kasao River, in seven prahus with twenty-eight men, twenty-four of whom were Penihings, who, with their raja, as the chiefs are called on the Mahakam, had arrived from below by appointment. Owing to my recent distressing experience I was not sorry to say farewell to Data Laong, where the women and children were afraid of me to the last, on account of my desire to have them photographed. The Saputans are kind, but their intellect is of a low order, and the unusual prevalence of skin disease renders them unattractive though always interesting subjects.