A laboratory investigation of 776 cases of labor pneumonia, mainly among Kenya Africans, over a period of 5 years, revealed a remarkable preponderance of infections due to group IV pneumococci.

Comparison of the total case mortality rate with the case mortality of group IV pneumonia infections suggests that Kenya Africans are not specially susceptible to pneumonia, and that many of the group IV pneumococci which cause pneumonia in Kenya are of high virulence and penetrative power.

A considerable number of group IV pneumococcal types capable of causing severe lobar pneumonia were serologically isolated. A few of these were identified with pneumococcal types prevalent in New York and South Africa.

An experiment was made on a fairly large scale with prophylactic antipneumonia vaccine, made in the same way as Sir Spencer Lister's pneumonia prophylactic which is used with success in the Rand mines, but constituted of the pneumococcal types which had been found to be most prevalent in pneumonia in the Nairobi district. Extensive trials with this vaccine have been made on the labourers of the Kenya gold fields, and elsewhere, and very encouraging reports on the effects of this vaccine in reducing the incidence and case mortality of pneumonia have been received from medical officers who carried out the inoculations.

A technique is described for the use of surface culture suspensions of pneumococci for serological and bile-solubility tests, and advantages are claimed on specified grounds for the use of surface culture suspensions in preparing agglutinating and therapeutic pneumococcal sera.

A method is described for the use of formol-saline suspensions of surface cultures for preserving collections of pneumococcal types, and for correlating pneumococcal types prevalent in different countries.