The F. M. S. Medical Report for 1912 provides a good instance, taken from the portion dealing with the Institute for Medical Research, Kuala Lumpur.
On page 25 it states that the occurrence of several cases of bubonic plague in and near Kuala Lumpur rendered it advisable to consider the possibility of the disease appearing as an epidemic and measures to avert such a calamity. A short paragraph refers to reported cases of plague, and then follow nearly four pages devoted to rats. Toward the bottom of the fourth page come the pregnant words: “Nearly 50 per cent. of the plague-infected rats came from the small stretch of Ampang Street, about 150 yards long.” The short description of this small area surely reveals a source of danger. “At the back of most of the houses there is a kitchen or bathing-place from which an open brick drain, covered with planks, runs through the house to the front of the shop and under the pavement of the five-foot way into one open drain at the side of the street. The plank covering of the house-drain is usually buried beneath sacks of grain or other heavy articles, so that the drain is not often cleaned. The open cement street-drain forms a convenient highway for rats, which can readily gain access to the house by the unprotected house-drains leading into it. Some eighty yards away the main drain empties into the Klang River, here a shallow and muddy stream with irregular, foul banks covered with reeds, rank grass and collections of garbage.” Now, who could expect rats to keep well in the vicinity of such a drain “not often cleaned,” and such a river, “shallow and muddy,” with “foul banks covered with collections of garbage”? Surely gratitude is due to the rodents, who, being nearer the level of the bad conditions, get ill first, and thus give human beings a fair warning of the sickness likely also to be their due, unless surroundings are made healthy for all animals, four-legged and two-legged. Yet, actually the Report has not a commentary upon these palpable ills, and, though it has by no means exhausted itself on the subject of rats, proceeds to vary the topic with fleas, the meteorological conditions that affect these high-jumpers, and the uses of guinea-pigs as flea-traps. The results of searching questions to medical men on the subject of flea bites are even given. “Of eighteen who replied one stated that he had never been bitten by a flea in his life” (p. 31). Most people must wish they were equally lucky. But not a single mention again of the uncleaned drains and the river choked with garbage during the course of pages all the more diverting because intended so seriously.