volume 1, issue 2772, P401-402 1914
DOI: 10.1136/bmj.1.2772.401
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J. Barr

Abstract: COR1tRES6PO0NDENCE._l_M that tllc relationi of suclh diseases to all tlle factors is-by no imieanis always a constanit relationi. That is to say that a very snmall increase of one of the factors may, under ccrtaiii conditions, cause a very large increase in the amiiount of the disease. Thlus, for malaria, I calculate that if tlle imialaria-bearing lilosquitos in a locality lhave a ccrtaiu low ratio to the lhuman beings-wlliclh I call the crlitical ratio-the disease will only just be able to maintain itself i…

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