This is a report on the findings obtained through the experience of treating 115 cases of diphtheria-all of them inhabitants of the middle part of Tottori Prefecture, a rural area, who contracted the disease during the period of 5 years between April 1954 and March 1959.
1. Incidence of diphtheria has been observed to increase since 1956. The epidemic season for this disease depends upon the climatic conditions of each district, and in the middle part of Tottori Prefecture it covers October, November and December.
2. The most susceptible ages are, from 3 to 6 years, without sex difference.
3. In the light of the conditions of local psudo-membrane and of or around the lymph nodes of the neck, disease conditions have been classified into 9 categories. A certain level of parallelism was seen between this classification and prognosis or appearance of postdiphtheritic paralysis. On the other hand the study of the relationship between the classification and body temperatures produced negative result. In view of these findings as well as of the fact that there were 11 cases (9.6%) who showed no fever throughout the course of the illness, it is concluded that the more important items for diagnosing the seriousness of this disease are local signs and signs of the neck, and that body temperature is diagnostically not so valuable.