The return of the increase of large mononuclears to normal may be used as an index to cure. Walker and Emrich have recently reported success in treatment of cyst carriers by giving oil of chenopodium in 3 hourly doses of 16 minims, followed by castor oil and preceded by a dose of magnesium sulphate. CHAPTER XI LIVER ABSCESS HISTORY AND GEOGRAPHICAL DISTRIBUTION =History.=—Although Hippocrates noted the method of evacuating abscess of the liver by caustics there was very little known about the condition until during the last century. The history in connection with the finding of amoebae in liver abscesses is of very recent date (1887) and is taken up under the history of amoebic dysentery. =Geographical Distribution.=—Concisely one may state that the distribution of liver abscess is in relation to the existence of amoebic dysentery. It is particularly prevalent in those centers of amoebic infection where there are many white men having little knowledge of the conditions necessary for the maintenance of health in the tropics. In liver abscess, as with blackwater fever, it is education rather than acclimatization that brings about a diminution of these tropical diseases. For several years subsequent to the American occupation of the Philippines amoebic dysentery and liver abscess were common but in more recent years liver abscess has become rare in Americans and amoebic dysentery much reduced in prevalence. More temperate living results in less storing up of fat in the liver and an organ more resistant to infection. ETIOLOGY AND EPIDEMIOLOGY =Etiology.=—The dislodgment of amoebae-containing material from amoebic intestinal ulcerations and the plugging of the portal capillaries by such emboli give us the starting point of a liver abscess. The exciting cause is _Entamoeba histolytica_ which in the liver continues the same production of a gelatinous necrosis as is carried on in the submucosa of the large intestine or appendix. This pathogenic amoeba is fully described under amoebic dysentery. As to obtaining a history of amoebic dysentery in liver abscess cases we have the following statistics: 500 cases with dysentery findings in 60% (Kartulis). 444 cases with dysentery findings in 59% (Zancarol). 500 cases with dysentery findings in 85% (Kelsch and Kiener). 63 cases with dysentery findings in 90.5% (Rogers). 38 cases with dysentery findings in 85% (Seamen’s hospital autopsies). Amoebic liver abscess is exceedingly rare among children and probably 10 times less common among women than men. Of 40 cases of liver abscess Waring noted intemperance in 67.5% and authorities generally insist upon the importance of the abuse of alcohol as a predisposing factor.