4S(i IV (;nNri:iii,\(:K i\ti;i;\\ti(i\\i,i-: hk i.knktioi'k. 



pivlcnil l'iiiic Ir ii.iliiralislc puiir ('■liidicr li's ("'Ires vi\;iiils. I);iii- ;iu(Uii i;i-- Ic- 

 0X|)('-r'im(Mil,-ili'iirs ne conniiissciil l;i lolnlilr des coiidil ioii- <l,iii'~ Ic-iiiirllc^ il- 

 ii|i(''i'('iil , mais il r.iiil cl il siiflil (|iii' rrllVI <lcs i-oiidilions, ii^iioi^'-cs mi lai^'-i'-r^ 

 <li' (•(M('', soi!, |ii-;di(|U('iuiMil uni rcl.il i\ ciiiriil :i rcll'cj des condilions (•(Hiiiuf's cl 

 dclerniiiiécs. Si l'uii i-(iiiii,iil cl |ii'iil nicsiiicr les cniidiliuiis de \ ii' dcsclrc'- 

 off^'aiiiscs, MNcc une ,i|)|iii)\ iinalicni siij'ji'-anlc du i^'lcriiiinisiiic |iiinr |ii-i'\()ir 

 i|iic, Iclles conditions (danl rc'alisccs. Icllcs clioscs se ])iisscroMl. on |iiHiiia 

 enl i(>|ii('iidrc alors, au l'iir cl à mesiiro des observnlions, les géncrali'-al ii iiis (|iii 

 iiii'l I rend la si-iciice de la \ic an iiixean îles anires science--. 



VARIATION AND CONDITIONS 

 DROSOPHILA GROWN UNDER STERILE CONDITIONS 



SIMMAin 



In lliis conmiiinicalinn, liic aiilhors aini al siio\\ini^- llial in in-der lo oMain 

 relialde rcsnils in slinlyint;- any organism, for example Ih-usaii/iilii , IVoni an\ 

 |H)inl i>( \ic\\. Iinl c'-|ie(ially IVom llie evolulionary sland-poini, il is osvcnlial 

 llial llie Condilions in wincli llic oii^anism exisis slionlil lie precisely ri^gnialed. 

 'I'Ik' aidlioi's lia\c ii'coi^nised Uns al'ler c\|)crimcnls conliiined l'or llirec yenis 

 on qucslions (iT lieicdil \ . and on llic \arialions in llic neiAahire of I lie winn-. 

 \n ])r<)f;oj)/iilii. 'i'Iiey liavc l'ound a suilalile inclhod. and lia\e a<-liially urow n 

 livc i^'cneral ions ol' /). niDjii'Ioji/iiln. and onc of II. ciinfiiad. in altsoliilely ~lci-ile 

 condilions. Tlic inelhod will lie dcsci-ilii'd a>- precisely as possilde in llic c,i-i' 

 ol' piiysico-(dicniical c<nidilions. 



The anihors lia\e aircady oMaincil pi'ool's wliicli eiialile llieni lo aflinn 

 llial ail lho--c cxpiM'inicnls ol' \\ liicli nian\ lia\ c lie en perrornied in receni xcar-. 

 and specialh in .\nicrica. ou Ih-u^ujildlit. niu--l uei-i'v-.aril\ i;ive uui'clialilc 

 rcsnils. l'oi' llie reasoii llial llie uiideleriuincd \arialions iii IIk' eondilioii^ and 

 surrouudiuL;s niiisl iiiask llii' di'lcnniualion^ wliicli are llie olijecl ni' llie 

 researcli. 



As rct^aivN llie work ol' llic aiillior^. llie lacis deii\cd l'roin cxpcriiiicnl- 

 conliiincd for li\i' geiieral.ions in mic ca--c. aiid onc i^'cncraliou in llie ollier 

 case, ai'c iiol ol' siiflicienl cxlenl lo draw any <lednclioii l'roni excepi llial ol' llii> 

 nece.ssily ol' tliis mclliiMl. 'riicylia\e already. Iiy iisinii' llicir précise uiclliod. 

 oldaincd a cunslam-y aiid reL;ularil\ in llicir re^iilK w liicli caniiol lie couiparcd 

 w il 11 II le iiic(diereiice (d' prc\ iiiiis (disi'r\ allons. Tlicir (d'I'orls arc si il! resl ri(ded 

 lo perrecliiiL; llicir uielliods; lud'orc al lciu|il iiii; lo di~co\cr Imw llie ori;anisiu 

 sliidi<'d uia\ reacl lo varialioiis in llie condilious. I licy lia\e allenipli>d lo lind 

 llieuiosl ra\ oiiraldc condilioii'- bol 11 l'or I lie ind i\ idii.ii. and l'or llic rcprniliic- 

 livc l'iiucliniiv. lînlh liic-^c condilions are liillilled liy llie n^e of oiir -lerilc 

 niedia, and llial iii a liif; lier dei;ree lliaii lias licen knowii pre\ioii-l\. cillierin 

 ualural or arlilicial ccnidilions. l''or inslancc llii> dcsccndaiils ol' a •-iiiLjle 

 ll\. in onc rcccplaclc. in llie course ii\' Ic^s lliaii a nionlli. niii~l lie c(iiiiileil 

 li\ niillion*-. and ycl I liere ar(> no dcallis. and noue of llie uiinici'oiis aiioiiia 

 lies wliicli l'ormerly w ci'c ^o oricii iiicl willi. sindi as iniililaled (ir recnr\ed 

 w iuii's. or di^lendcd w intjs (aiioiiialle-- \\lii(li in soiiic cases, niii;lil lin\e liecii 

 rcijarih'd a^ lunlalions. accordiui; lo llie slaleuieiils ol' ccrlain aiillioi~i. lu 



