TOXKITY ' >l ( IXYGEN FOR PROTOZOA IX VIVO AXD 



IX YITRO: ANIMALS DEFAUNATED 



WITHOUT INJURY. 



L. R. CLEVELAND.* 



CONTENTS. 



PAGE 



INTKOUI 455 



MATERIAL. 456 



Mi.ni"!.- 457 



1 . 7 . r "::' 457 



2.' 4^0 



ms . . . 461 



-1- 1 . 4'<l 



$. < Salamind>rt 



4^.4 



row Frog. Rat. and Man in Culture .... 



8. 1 ' 'rolozoa. . 4', 5 



I.USIONS . 



Kll I ED 



INTRODUCTION. 



Tin- l.n't ih.it oxygen in an excessive amount is toxic for m. nu- 

 ll nut .ill forms of life \\as first demonstrated by the nunu-ruii^ .UK I 

 very tlioioiiji experiments of Paul Bert ('74). But tin- -\\irn 

 Itl.iddt 'im- fishes normally contain oxygen at a pn ---ure of 



[OO atmospheres (Haldane, '22). The cells lining tin- bladder 

 apparently .ire acclimatized to the oxygen. On the otlirr h.md, 

 I'iittcr '"5 . \\mking on the respiration of protu/".i. states iliat 

 p.n.i-itir tunii~. -tn h, for instance, as pa Una, li\vd in.in\ d,i\ > in 

 .1 iiKtliuin fnmi \\hich practically all the free (gaseous c\\uL-n 

 had luin rrnio\rd. In \'ie\v of the work of I'iitlcr and that 

 ( I in i tt'il liy 1 1 ah la IK- it occurred to me that a stud\ <>f t IK- toxii-ity 

 of o\\^i-n for tin- parasitic protozoa of many animal^ would be a 

 uurthy uiKlcrt.ikii j 



\\'i'ud-iMtinu termites have the mo>t abundant and the most 

 \aiird ruto/oan t.inna of all animal> that ha\'e been studied. 



1 Fellow (in the Biological Sciences) of the National Research Council, working 

 at the Department >t M..] '"gy. School of Hygiene and Public Health, 



Julius Hopkins I'nivi-rsity. Baltimore, Maryland. 



455 



