BEn.WIOlR OF l!At TKKIA. ^J^ 



y. 212.2^^20;^^. Non-niotile organism of doniinantly bac- 

 terial habit, .3/x. to .5/x in Ijreadtb. and .S/jl to 2/i, in length. Simi- 

 lar in general growth characters to (d, but colonies grow rather 

 more slowly, and are more opaque in the centre. Agar growth 

 is more viscid and potato growth is feeble. Bouillon growth is 

 also somewhat different, and a marked tendency to flaky film 

 formation is shown. I^itmus milk remains practically unchanged. 

 Grows freely in arsenite bouillon u]) to concentrations of i per 

 cent. AsoO^, but is inhibited at 1.5 per cent. 



5. 212.3333033. Vigorously motile with two to four uni- 

 polar Hagella. Breadth .3/x to .5/x; length .G/x to 2^10. Gram 

 negative. Bouillon turbid in 24 hours ; flaky, easily dispersed 

 sediment a few days later; goes alkaline. No Indol. Agar 

 colonies 1 to 2 mm. in 48 hours, and up to 3 mm. in a few days; 

 roimd. glistening, fairly translucent, and sometimes iridescent 

 at first, edge entire or slightly undulate, interior granular. 

 Growth on agar slope rapid, abundant, flat, grey-white, glistening, 

 soft, but not viscid ; at first keeping fairly close to the track of 

 the loop; water of condensation clear, with white sediment. 

 Little or no odour. Stab culture is filiform and uncharacteristic, 

 with slowly spreading surface growth. Litmus milk goes slowly 

 but markedly alkaline; little, if any. clarification. Growth on 

 ])Otato is good, translucent, and soft at first, later denser and 

 more opaque; non-chromogenic at first, but yellowish-brown 

 after a week or two. Grows readily in bom'llon containing i per 

 cent. AsvOg as sodium arsenite. 



6. 212.3333023. Grows readily in .8 per cent. AsoOg as 

 arsenite bouillon, but not in i per cent. Resembles S in mor- 

 phology and general characteristics. Is distinguished by single 

 unipolar flagella. delicate, but characteristic surface film forma- 

 tion in bouillon, distinct amylolytic action, well marked pinkish- 

 brown growth on potato, and more villous gro\\tli in gelatine 

 stab. 



(d) Streptothrix group: Two members were examined, one 

 isolated from soil, and one pathogenic streptothrix i)roducing skin 

 lesions in sheep. Both were intolerant of arsenite. falling to 

 grow in bouillon containing o.i per cent. AsaO..,. 



(e) Yeasts: No yeasts were identified and subjected to 

 examination, but several, including a pink yeast occurring in 

 dip and faeces, were found growing on agar plates containing 

 0.5 per cent. AsoO., as arsenite. Yeasts in general are known to 

 be fairly tolerant of arsenic. 



(/) Moitlds: Several moulds cropped up on arsenical plates, 

 but were not studied in detail. Penicilliiiin glaitcitm was found 

 capable of tolerating at least r per cent, of arsenite. It would 

 appear that most moulds tolerate arsenic fairly well, although 

 limits of tolerance do not seem to be recorded in the literature 

 accessible to us. The references accessible to us deal only with 

 the production of organic derivatives of arsine ; work in which 

 low concentrations of arsenic were etnployed. 



