HEALTH AND POPULATION 563 



authorities, each with a separate cHnic. Unfortunately an unfore- 

 seen factor, the spread of sleeping sickness into the district, altered 

 drastically the normal life of the population; during the period 

 of observation many people died of or suffered from the disease, 

 and others were removed from their homes into fly-free areas. 

 Although the value of the investigation was much reduced by 

 this epidemic, the results are of great interest for the study of 

 methods to be employed in such work. They illustrate the limited 

 value of observations made over a short period in view of the high 

 degree to which African population figures are affected by emigra- 

 tion and immigration. To mention a few of the results, during 

 the four years of the study more males were born than females, 

 but the mortality among male children was higher; the average 

 period of married life in the area was i i-g years before dissolution 

 by separation or death; the average number of living children per 

 woman was 1*5, but there was a high percentage of miscarriages 

 and abortion owing to syphilis; the percentage of women with a 

 syphilitic history was 59* 2, but including other venereal diseases 

 and yaws it was 89-3. In addition to these general data, a specific 

 medical survey was made of four villages with a population of 

 1,910 persons, and Dr. Lester's report contains cultural studies 

 which illustrate the possibilities of this kind of survey. 



During the same period another intensive investigation, under 

 Dr. G. R. Phillips, was made in the Digo District of Kenya in 

 connection with the campaign against helminthiasis in that area 

 {see page 552). Although the period was too short to produce 

 vital records of real value, many suggestive data have been re- 

 corded in the medical department reports (Kenya 1932, D.R., 

 pp. 13-25; 1933, D.R., pp. 17-25, and Phillips 1932). In Kenya 

 also for six months during 1930 and 1931 a rather similar study 

 was made of the Masai to produce data on a typical pastoral 

 tribe. By comparison with the Digo, the Masai showed little 

 malaria and only a small degree of infection with hookworm; 

 but on the other hand the incidence of tapeworm, roundworm, 

 pyorrhoea, and eye affections was high. The mortality of infants 

 and children bordered on 500 per thousand births compared with 

 about 100 or so among the Digo, while some 34 per cent of the 

 Masai women appeared to be sterile owing to gonorrhoea. This 



