( -^.'^2 ) 



hoïwii^ causcMl \)\ tlic loiiiili cliiiialc and increased liy llie sinokiii<>' 

 of" hadly |)i'e|)ared tohacco. which cncii \crv aoiiiil!,- clnhlreii Ix'uiii 

 ajul wliich is hehl lo lie a reiiiody a<i;aiiist ('oiiiihiiiu'. 



Thoii<i:h luoi-c aciil<- iiiahii-ia cases occurred, when tlie j'()ii,L>h. cold 

 woalliei- set in ^vith \ ioh'iil shou crs, there Avas nol anv ([neslion 

 ot' a chronic infection of the popuhition, manifesting it^^elf in an 

 enlarged, liar«lened inih in the chihh-en. Tliis agrees witli llie well- 

 Uiiowii fact, that in a rouglier cohler climate malaria generally 

 decreases in xioience. 



As bronchitis and its consecineiices do not niakc their enfeeblinj»' 

 inflnence fell on the constitution before a more mature age is reached 

 and are not to l>e coin|>ared in this i-espect with strong malaria- 

 infection, 1 believe to haxc found the chief factor (»f the pi-esent 

 difference of the two groups of the same tribe as to their consti- 

 tution and their character in the dillerence of the occurrence of malaria 

 as a conse(iueiU'e of the dilleience in height of the counti-y of the 

 liahaus and that of the Kciijas. 



Moi-eover I must take into account that syphilis is found in a less 

 violent degree among the Kenjas than among the Dahans. Among 

 some IJahau tribes it was so univei-sal, that I thought the fact 

 that onl\ tertiarv forms wci'c found could be explained bv assumi]i"- 

 exclusi\-ely hereditary transmission. Anuing the Kenjas. however, 

 syphilis was also met with oidy in that form, but the cases were 

 so isolated that W(> could not possibly ascribe them to hereditai'v in- 

 fluences, 'j'lie cases observed seemed to have a less injurious influence 

 on the general condition of the Kenjas than on that of the IJahaus. 

 That this endemic form of syphili.'^ is so unich less common and 

 that its symptoms are so much less dangei'ous among the Kenjas 

 than among the Bahaus is dn(> to a great extent to their stronger 

 constitution. 



if we now take into consideration, that among all these tril)es 

 every family, e\en thai of the chiefs is deix-ndent loi' its daily 

 food and sustenance» on tiie coiiliniial labour of all its members, 

 XN'hich is not the case in more highly civili/ed societies, we feel, hoxv 

 gi-eat the iidlueju'e must be which the more oi- less frefpient occur- 

 rence of these diseases must have on the pi-osj)ei'ity of the tribe. 



A striking cxamph* of the better conditi(»ns of existence ofiered by 

 Apo Kajan wliich is of e(pial extent to the L'|»per-.Mahakam, com- 

 pared with the lower river-basins, is furnished by the fact that for 

 centuries many ti-il)es have been leaving this country for other parts 

 of the w(M'ld and thai nevertheless the j)opulation there is at present 

 much denser than in other Daja|.v regiojis. 



