EXPERIMENTS ON BIRD MALARIA 393 



(It has already been tried on bird malaria, but it is impossible 

 to tell what species of parasite was concerned.) 



11. To make a comparative study of the effect of quinine and 

 plasmochin on the different species of avian parasite, and de- 

 termine whether all these species are equally affected. (Since 

 there are known to be such differences between the human 

 malarias.) 



12. Whether the effect of quinine and plasmochin can be laid to 

 any particular part of the molecule. (Much work has already 

 been done on this point but without conclusive results.) 



13. Whether, after large doses of plasmochin, infective birds are 

 any less infective to mosquitoes biting them within the next 

 two or three hours. (It has been found that quinine is with- 

 out such effect.) 



14. Whether plasmochin exerts any selective action on the gam- 

 etCK:\i:es of any of the species of bird malaria, as it is reputed 

 to do in the case of Plasmodium falciparum. 



15". Whether prolonged treatment with plasmochin would ever re- 

 sult in the complete sterilization of the treated bird. 



16. What effect, if any, plasmochin exerts on the parasites of 

 avian malaria in zntro. 



17. Is there any difference in degree of infectivity between the 

 blood of a plasmochin-treated case, and a case which has 

 spontaneously recovered ? 



B. The Parasite: 



18. \Miat the geographical distribution is of the species now 

 known. (Is there any grading into one another, as might be 

 expected if there is a close evolutionary relationship?) 



19. What the seasonal prevalence of infection with the different 

 species is. 



20. Whether cross-fertilization between gametocytes of the same 

 species is possible in the body of the mosquito. 



21. Whether there are actually periodical changes in virulence, 

 such as it is likely exist in human malaria, and which the 

 work of ]\lanwell suggests may exist in bird malaria. 



22. Whether continued asexual multiplication has any effect upon 

 the vitality of any of the known species. 



23. Whether the parasites produce a toxin of any sort, and if so, 

 what the nature of this toxin is. 



