My ten days’ stay at Merauke was a time of strange misfortune, and while there I had the unenviable opportunity of observing a very serious outbreak of a mysterious disease, which was said to be that deadly beri-beri, which has lately been occupying the minds of men of science. For some time there had been isolated cases among the Javanese convicts, but about the second week in April the Dutch authorities became greatly alarmed by the spread of the disease. Cases were reported daily, and all proved fatal. At last the deaths reached the terrible figure of 160 in ten days. The victims were all Javanese, the officials and natives went unscathed. The doctors of the Dutch Colony were very able men, but no relief could be given to the patient beyond administering anæsthetics. I question whether it was rightly styled beri-beri, for in South America, at Manaos on the Rio Negro, I have seen cases of the disease among the Portuguese rubber gatherers, but these bore no resemblance to the sickness at Merauke. The sufferers in South America were generally men who led isolated lives in the vast forests of the Amazons, gathering the sap of the _hevea braziliensis_, and living for long periods on bad food. Victims of this type of beri-beri generally live for nine months, and those of strong constitution and in whom the swelling had not risen above the knees recovered. If the patient lives the old life and continues the old diet in the forest, the disease gradually ascends until it gets above the knees, and then its course becomes very rapid until it reaches the heart. I myself caught beri-beri on the Rio Branco, and first noted its presence by the discovery of a numb spot about the size of a halfpenny on each ankle. The Brazilian medical men assured me that nowhere in South America could I hope to get better, and I was ordered to quit the country at once. Before I reached Havre the numbness was greatly reduced, the affected patch being then the size of a farthing, and two months after I reached home, it vanished. In Columbia I have observed exactly the same form of the disease as on the Amazons.