GEOGRAPHIC DISTRIBUTION OF MULTIPLE SCLEROSIS 



129 



10 20 30 40 50 



CEOGBAPmC LATITUDE ^N GEOMAGNETIC LATITUDE "N 



Fig. 3. Relative pre\alence of multiple sclerosis for the localities listed in Table II. 

 The sigmoid curve included in this and in subsequent figures is reproduced from that 

 for the geomagnetic plot in Fig. 2. 



Two surveys included in Table II are of special interest, for they were 



conducted at different latitudes in areas with almost the maximum possible 



range of difference between geographic and geomagnetic latitudes, i.e., in 



North America and Japan. Moreo\er, each of the two sur\eys included the 



1.0 r- + 



0.8 



0.6 



0.4 



0.2 



OL- 



30 40 50 60 20 30 40 50 60 



Geographic latitude °N Geomagnetic latitude °N 



Fig. 4. Relative prevalence of multiple sclerosis for four communities in North 

 America and Japan (see Table III). 



Footnotes to Table II on Facing Page 128 

 "1.0 corresponds to the mean prevalence for 50 or greater geomagnetic latitude (48 per 100.000). 

 l" Hyllested, K. (ed.) 1960. Report on the Geomedical Conference in Copenhagen, 1959. Studies in 

 Multiple Sclerosis III. Ada Psychiat. Neurol. Scand. 35, Suppl. 147, 158 pp. 

 <^ Provisional. 

 1 U.S.A. ' Canada. 



