Monocyte function of poison gas workers was determined and the following results were obtained.
1) No difference in cytostatic activity could be observed between poison gas workers and their controls.
2) Phagocytic activity of poison gas workers was slightly depressed when compared with that of the controls, but the difference was not significant. By duration of work, it was observed that the group with duration of work exceeding five years had a significantly lower value when compared with the group with duration of work being less than two years.
3) Chemotactic activity of poison gas workers tended to be depressed when compared with that of the controls. The activity tended to be more depressed the longer the duration of work.
4) A significant positive correlation was observed between cytostatic activity and phagocytic activity