[Read before Wellington Branch, October 27, 1943; received by the Editor, October 2, 1943; issued separately, December, 1943.]

These studies have been commenced with a view to determining the nature of the intestinal fauna of man in New Zealand. We present in this initial paper the data from the examination of stools of individuals selected at random from the inmates of a mental hospital in the North Island. The work of Dobel, Matthews and Smith, Boeck and Stiles, Bach, Svensson, and others have clearly established the fact that institutional life favours the dissemination of entozoa, and that in consequence of difficulties in personal hygiene the incidence of entozoa is commonly higher in mental hospitals than in other institutions or in the general community. A mental hospital is accordingly a good starting point for such studies as the present, and we are deeply indebted to Dr T. G. Gray, Director-General of the Mental Hospitals Department, and to Dr B. D. Hart, Medical Superintendent of the Porirua Mental Hospital, for the many facilities which they have so freely extended to us, and to Dr R. W. Medlicott, Medical Officer of the Porirua Mental Hospital, for his kindly interest, which has been invaluable.

The data obtained from the study of a single sample from each of 100 individuals form the basis of this report. Slightly more than half of the specimens were examined fresh, and the rest examined after preservation in 5 per cent. formalin. A minimum of three cover-slip preparations, when possible each from a different part of the sample, has been taken as the standard, though additional preparations are made when required, and in most cases four preparations have been examined. Each cover-slip is prepared to the optimum reading density as defined by Boeck and Stiles (1923), and Gram's iodine solution employed for differentiation; but saline, acidulated methyl green, and iron haematoxylin preparations are also put up when needed. The reading of the individual cover-slip averages fifteen minutes, and approximately 225 separate fields are examined in each preparation.

The incidence recorded for each of the species cannot be considered as the actual incidence of the entozoan in the group. The cyclical nature of egg-laying and of cyst-formation, and the probabilities of locating eggs or cysts in the small quantity of material which can be examined are both factors which enable infestations to escape detection. However, the examination of a single stool

has been a common standard in survey work. We have retained this standard, and our findings are reasonably comparable with those of Matthews and Smith (1919), Boeck and Stiles (1923), Meleney, Bishop and Leathers (1932), and others. Although the number of individuals in the group is small, random sampling has yielded a group of 44 individuals faulty or faulty at times in their habits, and a group of 56 individuals of normal behaviour in regard to their personal hygiene. It may be pointed out that this is not cross-sectional of the hospital community.