TOXICITY OF n\v<,i;x FOR PROTOZOA. 467 



role which insects play in the transmission of protozoa from man 

 to man, from animal to animal, from animal to man and from 

 plant to plant ran he worked out much more effectively. What 

 effect, if ;my. oxygenation would have on other insect-transmitted 

 organisms, bodies, inclusions, and agent- would he well worth 

 study. 



Earthworms when .\\ ^cn.ited lose their ciliates and are un- 

 injured hy the |>: 



I rogs harbnr many pmtn/na. More th.m 150 experiments 

 have 1" rried nut on tin - nation of fi. 'id .ill the 

 intestinal pmtn/n.i m.iy he remo\ed \\itlmut injury to the fr. 

 Table 1 1 shows the minimum time rei mired t.. kill th; 



ll< Mimitns, Polymastix and I 'id t\\o ciliates. < } fndina 



and \y< !i'!licrns. The ciliatc- .ire killed in le-- than one-half the 

 time required to kill the 1: :iid the flagellates in nnc-titth to 



one-tenth the time. 



Tin- |iml./na of two water breathing \ ei Mel uatt -. ^nldti-h and 

 salamandei -. uere all killed hy ilioii in le-- than one lifth 



tin- time n quired in kill their hn 



If ox\ ^nation \\ill remove the pmto/na nf ..ther amphibia, it 

 will he possible to make some inteic-tin^ -tudic- on pn>to/o.il host 



-|>ri lilt 11 \ . 



II i-- hivjily jn'ohahlr that all inte-tiii.il llam'llatf- and i ili.i 



ma\ he ienm\ ei| I' I'o m all in\ ei lehrale- and from all cold -hi led 



vertebrates h\ . ition and that iioni- of the-e ho-t- will he 



injured. It i> al>o |H.--ihU- that the >|>on ,/ ( .a. aiiui-ha', and 

 blood-inhabiting protn/oa ma\ he tenio\e<l fnun the -ame hosts 

 in the -anie \\a\ and \\itlmut injury to the ho-' 



Manx' rxpei iinent- ha\ e heen carried out on 1 ri< iionionas from 

 frog, rat and man in culture. All o! ihe-e pmto/<M are killed by 

 oxy^eiiation ; -ee tahle I for the minimum time), hut the time 

 required to kill them in all except the : longer than it takes 



to kill the ho-t it-ell' at the -aine piv--mv: so it is impossible to 

 remove the pmto/na from rat- and human beings by continmj; 

 them in oxy-i'ii at ,^..S at mo-| there-. I'eihap- i ma\ he 



successfulU' administered tn \\arm-hlooded \ertehrates in -nme 

 other way. \\'ork of this nature i- in pro n 



t >\\ -I'D at ion experiments ha\ e heen carried out On four genera 

 of free-living ciliates and t\vo of free^-living flagellate-. < )xygen 



