M (1) 10
suffered from dysentery during these five years is 37 in the Tung Wah, and the corresponding percentage in the government hospitals is 13; in the former case only Chinese are patients, and in the second case patients are derived from all nationalities. For the same period only 33 cases of abscess of the liver have been found recorded as occurring in three hospitals and the public mortuaries from which these statistics are derived. The total number of cases of abscess of the liver probably includes abscesses due to other causes than the amoeba of dysentery, but even if this be not taken into account, tropical abscess of the liver seems to be less frequent here than in other places in which amoebic dysentery is common, e.g. in parts of India. The presence of the amoeba histolytica does not seem to be the only factor in determining that dysentery or abscess of the liver shall follow, for it is considered as proven that the parasite exists in a proportion of people who have never been outside of the United Kingdom, and it is very seldom that either of these diseases are found in such persons.
Ankylostomiasis. The results obtained by different observers vary greatly almost certainly because of the different methods employed. For example, in 1913 the stools of 1,045 persons were examined in the Civil Hospital to ascertain the frequency with which various parasites occur and ankylostoma eggs were found in 11 per cent of the cases. Again in 1917 the stools of 500 prisoners were examined and the eggs were found in 22 per cent. The explanation of this inequality probably is that in the first series examined the sedimentation of the ova was not provided for. Very few cases of patients suffering from ankylostomiasis are returned from the various hospitals, the anaemic, dropsical patient is not as frequently seen as in other countries in which the disease abounds. But it is likely that some of the cases returned as being due to 'anaemia' or 'debility' are really cases of this infection. The number of emigrants examined by the health officers of the port during the last ten years was well over a million, and of these 13,471 were rejected for various reasons as physically unfit, but only 638 were rejected on account of anaemia. The figures are not exact as the examination could not be very thorough, but it is of some value as an indication of the frequency of infection with the hookworm. It is thought that 15% of the population of South China is infected with hookworms of one or other species, the ankylostoma duodenale being the commoner of the two kinds. The oil of chenopodium has been found effective in treatment, but the treatment of the infected in an area in which the disease is endemic is not a hopeful measure. The work of the Rockefeller investigators has proved that the worm lives not only in the surface of the soil but that it travels downwards to various levels thus rendering the treatment of the surface of the soil ineffective. The same enquirers have shown that the ordinary domestic animals, such as fowls and pigs, are capable of effecting the distribution of the immature forms of this parasite, and they have described a new species of ankylostome which is peculiar to the pig. The population in South China is not infected to the extent that obtains in the population of other places in the East. Possibly the custom of keeping the infected material in water-tight tanks is responsible