HOST-PARASITE RELATIONS I INTESTINAL PROTOZOA 



iodine solution or of methylene blue for flagellate infec- 

 tions. Such treatment might be efficacious against or- 

 ganisms such as the flagellate, Trichomonas hominis, 

 which lives in the lumen of the large intestine, but prob- 

 ably does not destroy organisms such as endamoebse and 

 coccidia that live in the v^^all of the intestine. In a similar 

 fashion certain investigators advise vaginal douches with 

 a saturated solution of sodium bicarbonate to destroy the 

 flagellate. Trichomonas vaginalis (Fig. 7), which ordi- 

 narily lives in the acid secretions of the vagina. 



It seems possible that drugs taken by mouth may act 

 directly upon the parasites within the intestine. loda- 

 moeha williamsi (Fig. 4a) is destroyed by the adminis- 

 tration of emetin although it lives in the lumen of the 

 intestine. In this case the emetin may kill the parasite 

 by actual contact. 



Progress in the chemotherapy of protozoan infections 

 has been most gratifying within the past two decades. 

 Quinine was already in use in the seventeenth century 

 as a cure for malaria, but only recently have satisfactory 

 therapeutic agents for other protozoan diseases been dis- 

 covered. Emetin was introduced by Sir Leonard Rogers 

 for amoebic dysentery in 1912 and soon came into gen- 

 eral use; more recently yatren and stovarsol have both 

 been proved to be specific agents for the cure of this dis- 

 ease. In 1905 Thomas inaugurated the treatment of 

 trypanosomiasis with atoxyl and to this have since been 

 added tartar emetic, tryparsamide, Bayer 205 and Pas- 

 teur 309. Tartar emetic which was discovered by Vianna 

 in 19 1 3 to be efficacious against American leishmaniosis, 

 has been found to be equally valuable for the treatment 



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