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When the results from both studies on the acute toxicitv of iatraperitoneally injected nicotine tartrate and acute s::zoke ir.:-:ala:ior. toxicity are taken into account, there remains no doubt that the 15. 16 line of inbred hamsters is the most appro- priate experimental at:irr:al model among the species and strains of rodents studied (see summary data in Table V). It is also aD- oarent that the 82. 62 and 87.20 inbred lines of hamsters share t: e second place with respect to tolerance toward nicotine admin- istratio^ cr w:^.ole smoke ir.halation. Since the animals from the 82. 62 strain are known to exhibit a high incidence of cardiomyo- pathic lea'cr.s and. _.,-see::ent1}•, to have a much shorter average survival e -:an 5 '. 2 C' :arnsters, the latter strain of anirr:a:s is uc° r:..,:•e s•.:i:az:> :cr ione-.erm st-,:dies than the former. _.._ _..ic ::ilalation sr,idv a. `.fortalit•. -;here was a verv low :ali.-: in a_: _r.til the animals were on exoerirner.tai z...._.=s ac:,•_: __ weeks (see Figures _ and 4); at that :::•:e -e:- aie was 73 w•ee;cs. _::ereafter, mortal:t;. c-easec .n --e e::oer.....ntai as well as in the control and .n e.._...cc- be ass:::::e_ by e::traooiaticn .., :.ati - reac-ec c_-c a:te:• .00 weeks. It is ev:dent ..,,... .: _ cata ... -_ -__ __..- .na: exoos;:re to s^:oke or to s::a:: -s....,.... ~ -._..._.._ _ :.c: . ne ......ta:tv c: the animals. C:anges in bed•. •.t•eiehts - _:ere v,er, cetw•een the two .nbred 1: nes of to c: a n;:es in 5odv weig::t '3DO:: exDesL're to _.:e _... c- cc :tr_:,. ..itions, as seen in Fie•.:res 5 anc ..._ _ .,_ _.-. r.es were started on the experir-:e nt at a..rnc wr.er. was approxin:ately 108 grams. The :age- r.e:c cZ'...r:.'. ar.::::a_s of tt.e 81.20 strain increased to an averase boc}• u•e:_::t of i-;-;. 3 grams, whereas the weight of the corresDcnc- inc controi a ni:::als of the 15. 16 line leveled off at a much lcu,er :::ark,. i.e. at 1 25. 0 grams (see Table VI). Exposure to cigarette smoke reduced the body u•eiz:: o: t:^.e ar.::::als of „ot : inored strains by abc•:t ten grams during t*-e first two weeks of treatment. Subsequently, their weights increased agair., but some~c•i:at more slowly in hamsters of the 15. 16 than in t::ose cf the 67. 2 0 l:ne. Because of the fact that the 15. 16 con:re: anir.:a:s cained cr.'. 1i:tle weie:^.t, but the 87, 20 control hamsters ir.creasec rr.ar kec:;: weight after the beginning of the expertr.:en :, -S- CTR HN 0422-484

the difference between sr::oke-exposed and cage-held control ::arr:- sters became much more important in the 87.20 than in the 15. 16 line. As shoa-n above, these marked differences in body weights did not affect, however, the mortality of the animals. Exoosure to sham-smoking conditions yielded bod.• weights that were intermediate between those of the smoke-exoosec hamsters and of the cage-held control animals in the 15. 16 line, but aoproac'.^.ec and even slightly exceeded the weights of the cage- held control anir•.:als irn the 87. 20 line (Table VI). :he d?-°ferences ir. body weights between the ar.i: :a':s of the experimental grot:> and those of each of the two control 2rc•.:ps were highly significant b;: stat:stical criteria (p S 0. 01) in the 87.20 inbred line at all tir::es (see :able VI, columns i and g); in the i-. :o line, the ditfer_..ces were sicni`.icant at certai., tir::es oniy..e. between -C and o~ wee:<s, and above 90 weeks of trea.r.en:. -r. s:~.e instances, t:ere was a significant difference betweern t^e two ccr.:r:~: groups (see =a*--.'. ee %•i, column n). .t t:::s acoears that the bod•: weight iosses of the e:.:- oer,:r:e::ta: an .•._a:<_ .,r :r.cre exactly the'.r failure .,: za:.. was d•.:e to t-.e e:'ects o. _..:o:e inhalatic n, rather .: an to n e s:`e== suffered by .: e an:ma:s _.;rir handling in the sm.o:ci ^:ac: ne. .:ss .,as not 1il::ited: notce:e~, .,. .:e an. :::als ^: t.Ae exDer-^:e::tal Crol:Ds. JoT.':ewRa: less r.:ari:e6 lossez were also O:~ser•:EC ln DO:: Ero.1Ds o: ::a^:s:ers ex:~csed tG s:.a:' :.- s^:o:..,E con d:.:en s as well a_ irn cage-neld contro: ar.-mals c: o: the two .. nes (o 7. 2:). _:is pheno:r:enon r::a.• be attr-butec. .:._ r :cre. at leas. ..n par ,.c stress endured 'o} t: e a::.r.:a:s ,•n en «...-- ec._stc^ ec ._ ..ear.. - tr.eir 'elt-alw:.i.^.ur collars, .r to stress __- soci~tec eti_,e-.^:e::tal conditior.s of forcec i= cb::;zat::-. t::e anirra.s ..n the s:-okinc chamber. c. Carbon monoxide content in blood - Car- boxyhemoglobi:: levels were determined in six male hamsters (1~_- 120 g body weight) of each inbred line at selected time intervals. This was performed by heart puncture of animals lightly anesthe- tized with nembutal (with 100~*o survival), before and ir:.mediatel;; after smoke exposure, four hours later (just before the second ex- posure of the day), 24 hours later (before exposure on the follow- ing day), as well as on a Monday morning before exposure (after srr:oke inhalation, twice a day, on four days during the preceding week). The animals used for this purpose were not the same as -9- r%l !~1 ~rl r" TIP r-nWTPC Q%1 Tc~ CTR HN 042 4BEEz

/ those used in the chror.ic inhalatiorn study, because the former were given a muc: ::igier smoke exposure than the latter (20 min- utes of exposure tu-ice a day, as opposed to eight minutes twice a day, each minute consisting of 17 seconds of 1:5.2 diluted smoke and 43 seconds oi fresn air inhalation in both instances). It was known that such severe conditions of smoke inhalation, as admin- istered in the blood carbon monoxide study, would not allow the animals to survive ::•tore than a few weeks. In addition, subjectio : of any animals of the long-range, chronic inhalation st•,:dy to the stress and possibla of repeated heart punctures was avoided. Sin ce E: c'.d not aonear indicated to carrv out pie heart puac:,:res a: s:ort :i^-ie intervals on the same animals, the data or. ca-box•:-e:::oglobin levels at the various staFes oi smoke :•hala:ion re=lec: •: e results obtained wit : six ir.divicual ha r.sters .n eac.c inbrec s::own in :ables VI: and ViII. _- :.ar.:ster_ c. bot :.•nes, :er e ras a mar::ed increase of carboxv: e:::ozie_:.. to between 20 and -_ ,.r:rr:ediately after exposure to s-r:oxe (see animals - and -: on ca.• C... =a~le VII, and ar.:rr.als _ and - crn da;: : in Table 1'ili;. -^ese nizh ie•re:s decreased within fo•sr ::ours to oet.c•een - and :::-, (=ee a ni:r.a:c 5 and b, on day 0... Table t'I: a nd on da~: :•.. Table se;.ond smoke exoosure on .ne same cav a.ain :-a:sec :ne ca.=c~ : e cglcbi .-aiues ir: .ne bicec •., be:•-A•e: 3G ar.c _ (see e..~..___ = ar.c c on ca. 7 in Table %'Ii, an c ar.::ra-s 2 anc - o r: _a•. ' .r. _ a :._ _ ... ter t«•o exposures _:ca-e:•: smo- -e w::i::m .'ou:• •., e •r.o;::•s and 15 to 1Chours of rest c,:r; , :e .. , caroc~::::e:r. -lob:r. ::ad r et•,:rned to near ore:-eat •_:e:_ ..n ai: ._s:an:_s ksee ar..:r.ais . and 2 o^ day r. =ao._ _ an,a cG 14ay - ... .co'-° V_:I). Carc-.. :r.or.ox:ce .vas al«•avs co.^.:7lete:•: ?5.....:c:?C c._.._ a:ter exposure, on one or on se._ra: co.. secur'.•.•e da•: s.o t•.%•o and or.e-half times greater doses _. cigare::e smoke than used :^ t: e long-term inhalation study (see all data a: 9:30 a. m. in Tables VII and VIII). Nevertheless, the mortality irn the 87. 20 line was considerably higher under these conditions than in the 15. 16 line of hamsters. It may be assumed that this differ- ence between the two inbred strains was not related to the toxic ef- fects of carbon monoxide, but rather to those of other smoke in- gredients, possibly including nicotine (see the higher susceptibilit;• of the 87.20 hamster to ir.traperitoneally adr.zir.istereC nicotine tartrate, _ ioure . and Table IV). E:COos::re of hamsters to cigarette smoke for m,.c.. r"11711-81 t,.,r f R f f N 0422486

shorter tirr.e Deriocs, i. e. for only eight minutes, twice a da;:, as used in the chronic in: alation study, may thus be assumed to cause no lasting accu_-nulation of carbon monoxide in the blood of the ex- perimental animals. This was actually confirmed experimentally in a few anirnals of both inbred lines, as seen from the data in Ta- ble IX. i d. Changes in serum triglyceride levels durinc s:no:ce exoos.::•e - The differences between the mean tri- glyceride leve'ss of ~.e four experimental groups of each of t:ze two inbrec 'i=es are not statistically significant, excep: that t::e;: were lower in .:e case of the young 877.20 ha:r:sters (Group :: ), as seen from tne cata of Table X. The increase of serur:: triF_'.;:c- erides during arir.c is a co.:.rmon occurrence in man and ani^:ais. T'-.e fact .:a: :....- an ._.crease ._n serur^ tr:£1yceride ecc;:rrec ..n the c'. _C ..r.e ar.c not ..n t~:e :3. 16 lin e of : a.^.:ste r s r:at• be a:- ....,,:tec to .: e..._.: s-~:ailer oody weight in.reases in .^e .~. ._ -:ne c•... .^ it: e..:::e ...te r ral s t•.:diec. =xoes--:re of the hamsters tc ci:arette smoke c:c not a::ec- serur.: .-igiycer.de 12•:eis in ei.ner of .:_ ..:o _...__ _..=e. .r.~est ::o e. _s -o:iles o: test ar ^:a:- _-c..: ea_.. crou~ were =ac=.--cec ar.c s rc:.._ :as s:__:ec a'ter ._ weeks on etiper.::•:enta: ccr.c: .,::s; e:ccosur_ t: s:~ok=_, expos.:re to s::ar::-smoi:ing ccnc:- .:o::: cr :aze-nc:c:. - ... acc.aon, s:•: an.rnals of eac:: .::bre_ _. e. «•: . .. =ec .._ • _ • oeer. ....der any exper.^:ental co :citio: c an_ -e,ocr.cec ... %ve:. .. and age to t: e ezper.r.:ental an :r::a.s a: %rere a:so i.^.ciudec n .ae virus s:...:es. ... Tables XI and XII. These data .'-ear. i::cicate that, ,•• a:i .r.stances, the virus pro:.le of the an.r::a'.s .:as not changed b;: exposure of ha^:sters to cigarette smoke or to co: - trol conditicns. f. Influence of smoke exposure on absolute orean weights at autoosti• - After 45 weeks of smoke exposure, or exposure to s::a:::-s:^oking conditions, or maintaining the anirnals under control conditions (cage-held controls), six hamsters -°rorrm each of the six groups, as well as six young untreated control an:- r.:ais frer:: each c.° the two inbred lines w•hic : never had worn fel:- alumi nu~: collars a nc whose a¢es and body weights were analogo_s to those of the anirr.a'.s at the beginning of the study (107 = 3 gra:::s r-"TP n'O~,O`I%I c`TR 11N 04*22487

body weight), were sacrificed and autoosied. The results on the weights of their organs are shown in Tables IX and X. The fact that the organs of the initial control ar.i- mals (identified as Groups CC and FF) were significantly lighter in many ir.stances than those of the animals from all other groups, can be interpreted simply on account of age differences. These findings were to be expected and are without importance. Apart from these organ weight differences, d•.:e to age differe::::a:s c: t.^e anir::ais, there were only a few instanc_s in whicFh sn:o:e exoos•.:re or sha:r.-smoking conditions may have induced sig ni::can t c'r.anges ... organ weights. These are (:) ir.- creased adrenal .c•ei¢hts in aniraals exposed to sharr.-smoking con - _itions o: ..ct :.nbrec lines, out not in the smoke-exoosec har.:- s:ers; (2) ......rease.. •x•ei_^.ts of the lun gs (ir.ciuding trachea) ... ._. 16 harr.sters exposec to s::a:r:-srr.okinc conditions; (3) decreasec 1:•:er and :kic=e•: w•eig-ts in sraoke-etoosed hamsters of the o". _- _:ne ori\• an: f.=j Cecreased soiee:: •.i•eigt:ts ..n sr.-.oke-ex7:sed ..'. 2: ha: :sters a nc. .., a....:c : lesser exter.t, ..n the contre': an irrals c' ....s iir.e, e>--sec t; _:a: s,--:e',.ir:g cor.d:tions. -: esc _a:a are di-_....., to ir.teraret. 5•.:bsec_e-.. aa corr_par:s_=s were :r.ade crn bas:s cf .^e reiatire organ s, aii•.:ence o: sn:ore exoos•.:re c:: re:a::%•_ zar. ~e:-- -..-- ..-zan w•e:ghts were referred to a star.carz ..cd; .v~ ; .. c: ~DO g-a: :s, by di •id:^c eac.h organ \ti•eig :t b-: .: - .: F sarr.e a:::r.:ai on aucops: (in ¢rar s), and ... ... .:C. The results are st...unari:.ec in :a_.=z data allow tLe fcl:ck•in¢ conc:~sior.s: (:) There were no apparent di-'fer- ences in relat:•:e organ weights between ar -mals of the two tnbrec lines; this is t:-ue for each of the four age groups studied, as a•el': as for all s:x major organs analyzed in this manner; i. e. liver, spleen, kidnevs, adrenals, heart and lungs, the latter includinc also the trachea. (2) Relative organ weights tended -7 to increase with advancing age in all instances, experimental and centr ei Ere::ps alike; they also became generally more variable m 2 .c•it:: increasing age, in olde r an'.:: a'-s. as evidenced by higher standard deviation s t.f1 N ~ ~ CTR I I I I 0I2•8WJ'

(3) The increase in relative organ weights with advancin g age was particularly marked in the case of the kidneys, and was equally observed in both inbred strains; this was due to deposition of amyloid; renal amyloidosis was, in fact, the leading cause of death in hamsters in this experiment. (4) In the adrenals, the increase in relative organ weight upon aging in both inbred hamster strains was the conseoLence of a variety of processes which could be rec- ognized microscopically. The prevalence of these age changes precluded use o_' &crenal weight as a measure of stress. (5) There occur lower relative spleen weights in s:: oke-etpcs2d and in "shar:.-smoked" ha.^.zsters of the 57.20 strairn t: an :n t: e ca¢e- :eld control animals, esoecially be- tween -C and ZG ..ze::s ..` the exoerir::ent; this differer.ce :-:aN• rec- resent a stress effec: (cissoiuticrr of 1,,-mphocytes), but disaopears later in the experi:::en. (over 90 weeks) when diseases affecting :::e soieen becan :.: oe :::a:::fest; no sLc:: effect is d:scernible in the _. lo lir.e of : a:: _-_:•s. (o) There were no w•eig:^.t changes :n liver, spieen,..-cne~: s.,s adrenais, .vhich couid be attributed to sr::oicir.g, w•:t: a.e x....r.or ezceptions whic : are probabi.; of no im- ocrtar.ce, these _..ce- . ..s were increases ... liver and 'r.idne.• o: both strains ir. s:::c::e-exoosec ar.ir als, but only during the ea rl:er stages ci the ezner...._r.. (40 to 60 weeks); ..n most ir.star.ces~ .::ese d::ferences ~~er_ s:.a::s.icallv s:_ni-icar.t only at the :r; cC^.ri~denc cdencc level (see Tab:es X'•: and X",'ii). (7) Relative heart .veigi:s of =arns:e-- exoosec: to S:::o:ce :or .-.,... -:0 to 60 weeks were markedlv and si,-- nifica nti}• greater (. ~ G. 01) in both strains than those of the a::r:ais of both of the ccrresponding control groups (Table XIX); in 87.20 hamsters, the hearts of smoke-exposed animals were still signifi- cantly heavier than those of the cage-held controls aSter from 60 a nd 75 weeks, but this difference disappeared as the experiment pro- gressed; in contrast to the animals of the 87. 20 line, there were many extremely large hearts in hamsters of the 15. 16 line after ~C• weeks of smoke exposure, but none in the control groups; this ob- servation may represent an important, smoke exoosure. strain-limited effect of ---I m ~ (8) Lung weights showed no syste^:- U'1 N atic differences between experimental and control animals of the ~ -13- ~.~ra n t-n Ci R f i i 3 0422489

-5. 16 line Lr:i: a:er ~0 weeks, when the lun¢s of smoke-expesec hamsters became si¢nificantiy heavier (p 5 0.01) than those o: tae control ani:r.als (Table XX); i.^n the 87. 20 hamsters, however, h,:ng weights of smoice-exposed anir: als were consistently higher than those of the control animals and, by 90 weeks, exceeded the weie::ts of the lun¢s of caoe-::eld controls by about 50°,'0; because oi the rather large variability of the individual values (high standard devia:ior.s) during the later stages of the exoeriment, tae statistical significan ce of these d:f-erences :s somewhat reduced. ... Listooatholo¢_ical: ndin¢s - Rela::%•e'.•: few anir•.:a's_ s'_ e e-e :cs: ._. :istclogical stucies; losses were c::e t: cannibalis::•: ar.cic: c_ca.: of carcasses o: an imals t-at had ciec soor.taneou, siy. ~e:er. eless, 7S. Y": of a-i hamsters, with .he exoeri.•....: ha_ oeen beeu::. could be used for ..:stooa:4ol-_g:c s:,:dies (see =azoie ::1:), a : :ax:r.-ur.: loss in Croup C (s.. _. _- evoosec 15. - :a:-s:ers; •.c•:ere s:iil two-:...ras c: all ani:::a:: V:_r: s:adied Of .r.e 7:'r•a::zs:e: s wi:ic: c:ec soon:a':eous., cn.~ were s• i:ac:e :os ..:s:ciogic s ~c; , cause c' =eat c_ :d be es.ac- ..s:ze. .-s:ar.ze_. as seen . =ab:e ?:X~. : ena: a: .~ic:cos._ -.tas t: _.•_cs: c:..:se .,- dea:.. .•n prac.Ecaii}• a:_ gr,,,::)s. here ex:s:- .•.. ac-=-=-•. re:a:ior.s::o between cause of dea::: an~ ..._ exce=:~r. „- t~_ .,..re:::.e c: :V:c na:_-:a:,.ncea: ._:::cr: ... ~.:rc:.. :. (s:r.c.Ke-eX- Zse:. .:. . _ :.ar.:_-_. . oose: :a:.cns ,.n t=.e ._ss.._- _- c.. :_- r.a:-:=.,-s are rece.cec ... =acies Xti:_ .... ..=se cat ~: _ a-ra^zec crZar. cr sae ('.z~ .rac :ea. r.eart, '.'.:er. sp_ee^, k:cr.e: = and ac. _ ,...- _-rain c'`r.a:nsters (15. 16 or 87.20 li.^.es), b}• t::e experimental conc:t:cns used (groups of smoke-exposed animals and of "sna:::-smokec" or cage-held control animals), and t::e•: are subdiv;ded into four arbitrarily selected time per:ods of ex- posure to the exoeri:-:ental conditions (40 to 60 weeks, 60 to 75 weeks, 75 to ~0 weeks and over 90 weeks). _.ar%-nx - Bv far the most impcrta::: ~ indings in ...is exper.ment occurred in the larynx. Sixty-six per ~ cent of the larvnxes .rom the 15.:6 line of hamsters and 6-1-; cf those _ror:-: :e S7.'_C line were examined histologically. Among t;-.e sr^oke-exposed l:a:-:zsters, only two out oi 48 tissues from t`:e tr'1 N %Z O ,~ .~ _"'Y~.wy L.~ Tf"G ~ f i`~ S..A `~' L' ~ 0

15. 16 line a nd t:ree out of 45 tissues .ror.: tae 87 .20 line (7~~) were reeardec as '.istologicalir normal, as opposed to .rom 68 tc =~~, of the lary :xes fr orr the corresponding control animals (see Tables XXIII and XXI%', colurr.n v). The pathological changes, limited ex- clusively to the lar}-rLx of smoke-exposed hamsters, were of the fol- lowing three kinds: Leukooiakia - This was defi::ec (loosel,: after po:aen•wiil) as t::ickening and hyperplasia of the so;:a- rr.ous epithe::•,:::°: c' t: e larvr_x in which all the growth occurred up- tt•ard tcw•arc .: e-_--...... _: e basal laver remained intact and :air-* straiCat. ?_ .. :a::ia ceL'.c be associated with nuclear dyspiasia tt•:ic': was us•.:a:'.•: r:•::'_c tc :::ec•rate in de¢ree. This was seen in =G~c of ,r.e iar• :xe s o: t::e 15. : c 1ine, and ..- B 317o of thcse of t:e c'. ? C __r.e (colu:r:.. . . -c.._-_ XX:._ ar.d XXIN'). Pseurioeoithelio-:atcus :asia -:'.::s tt•a_ :.e -.n_z as , ration of t: e squar::ous epit::e:•_..e c: t:e :ar} _.n ...c-. -: e =asa: :a;"er of cells becar::e .-recuiar, a: :east par_ --e _cc_•red dow•nt.ar_s into the stror::a. --is ~e c' grc.._.. .:as ..._._ c:•.ar_c-_-.stic o` .r:e 1:.'-„ ha::•isters, ..rere as .-.e casz- as co.- car_,. .rith o ::t 3'. .:. -. ~. -..._ __ ..tern asscc:atec . .... ,:c :ar.cec ..,.:.:ea- c•. a~ -cr.. a:__ :e__ r.es:= ceep in t:e st-or-:a, ....toric .- Cc2^ Cel._, a.^.: a:2-..=tan:es Of DOssl--:e 1~?'mD^.a::.: 1.^.•:asio:. zL-s:ec - ess...- ... ear :asive ca- -:or•:a. ., ..._:an...:_ an ar.--•._.. . n.s :-ar_- •.t•as icund n 19"', of t .._ an-r.•.a:s :- 1=. .c ...._, a: _ ... .... • - c: .^e ::az:sters :aoles :_n_ I'apilioma formation - Sma:: scuar::ous papillo:::as, s:milar :o those occurring irn the trachea and bronchi, Nvere fo;:::d in the laryngeal epithelium of 25°,'0 of srr.c::e- exposed 87.20 aai:::als and in 15-, of the 1ti . 16 hamsters (colur:-.: :x, Tables XXII: and XXI%'). Occasionally there was pseudoepitl:elic-n- atous r;:peraiasia at the base of oapillo.^_zas. A few iarvnYe_ o: s::zoke-exoosed hamsters also s: owec chrc•.:c ir`lasrLMat;crn and/or seuar::ous metaoiasia o: ..._ ccus E:ar.ds icc'.-.:M~_ns x and x:). Chronic i-2iarrmatior GCCI:r rec, - i5- crR HN 0424, 91

however, also i n the control an ir::ais. The mild chror.:c .. :am. matio : w•'r.ic: occurred in the "sharr.-smoked" and in the cage-'r.eic control animals might be associated with slight epithelial thicker.- ing, but never with franic leukoplakia, pseudoeoitheliomatous hype:•- plasia or papiiloma fcrmation. There was no significant differe::ce between "sha^:-smoked" and cage-held animals in this respect. In a number of animals, the larynx was not exa^:- ined histolcgically, but was transplanted into the cheek pouc: oi otner : az::ste:s oi :: e same inbred line, .n order to detect Doss:- ble :_a'_igr.ant Lotent:a:. Lz th :s manner, the laryrYes frcr.: seve:: sn oke-expcsec ._:.a^ ste:_ (four after _-90 weeks, and three after r: ore t:.ar. °~ weeks o: smcke exposure) were transplanted into new i-7. ic hamsters. In acc:tion, 29 lar}'r-Nes from ha::ste:- ._ _ t: e..-. 2 0 _.^e (:er: a:ter -_ ?C- wee'r.s and 19 after more than •.vee:.= c: e::Dcs..:e) .:ere t:ar.-piantec ....c new• c-.'_C. :ar::s:e:•s. _ .r.a_:~ :e :ar. =tie. -:om " s:.ar s:r.o:;ed" cont:ol n a:r.s:er_ anc seven -.~.-n ca_ee ..-ic cor...=. animals, a11 e: the b'.2C 1:..d an d a:- a:te. .....re . nan -_ •x•ee;s ..::cer exce-.:-:ertai :ondit?c: _. «•ere .-ar.sc :r:eC ....c r.e.%- ST.=.. r.ar.:sters. Thi: exceri^:ent ., '.a": - :~:nett D2r:ent G: t:e _:c^: . ~. . _ nL.:..::e:s an _ . ~: . _. t.'.Jse -:o.^.:.tCe C ~ . 20 s::a:.. - e:c exa^-.~.n°= ..._.:_ ca'.:•. -n :S 'e•:ea:cd ~c:.. c'ea- ... s:._.-. c?i:=:e n: es and s~ nt e">_c.- -c s:no::e exoosur_. ..._c:oo :a_es .: bc..- s:ra:r.s c: ar..r.:a:s car. :o:... s:::a_. :._.. -s ... .: e :,a:en_. -:.a. _..._ ter.cer.c• is r:uc- ...:,-e .. :'. :: r.ar.:-:e: _ a::_ .s acce::..:atec b•, sr:.o::e ..n bc:.n st:a:..s. _....s, c-_r:pe_ r-a:.-cc::ages •.::e seen in 9-Tc e: t^_ _- :e : _ a'tee s roke ex:)osLre, b:t ..n or.lv .- ar.= .- • cf .-, two control g:oups of this strain (column vi, Table XXVI). S::a:a: clumps were seen ir. t::e 15. 16 line of hamsters, but more :a:ei.:, i. e. in 53•"'o of the srnoke-exaosed ar.i^:als and irn from zero to c-; in the two control groups (volurr.n vi, Table XXV). There were ^:orozoloeicai as well as numerica'l differences in ciur^pi ne among t::e various g:oups. In all ham- sters cf the ::. 16 line and irn the control animals of the 87.20 li-e, t::e c:•_^:ps cons:sted o: cc-r.pa:atively few, loosely packed. small :: acroD^aees co ntairar.e dark brown or blackish oiement. L^n the s^:oke-exposec 87. 20 animals, clumps were both muc^ larger and more abundant ir. the lung. More and larger macro- 11""TP Lr TR H{ ''f 0424922

phages were aggregated irn the clump and were freeuentiy mixed with a few po:•:mcr?!:onuclear leukocytes. Pigment, instead of being dark, was pale gold in color. These cells gave the Prussia n blue reaction for iron. The rare smoke-exposed 87. 20 hamsters which did net con tain such clumps were usually animals which were found dead in their cages of some intercurrent disease. Ectooic bone forr.:ation - About 2Q1~- cf :: e'.•,:ngs from 13. 16 hamsters contained small foci of bone :n t: e p~i:.onary parenchyma (columr. vii, Table XXV). T:.es: ..ere not associa:ed with ar.•; type of cellular re- action or an•: other ob~-ious disease process. Bone was found in '2°0 of the caee- ei_ controls of the 67. 20 line, in 2of the "sham-srrcked controls and i:: 12~'o of the sraoke-exposed ani- ^:als of a:a: ..ne icoi_..... v: , T able XX`: : he sign :icance ,,. .:is ossi::ca::c- ._ ...,' apparent. Adenor:^atosis - This ter:~ was used tc ___ --a:r :::eta?:asia o: flat a:'.'colar epit :eliu:r. ...._ columnar e? .r.e-.-... o_ the cronc::;elar •?e. There «•as a..ign si_ ..-ican: rence ..n t:at adeno~atosis occ•.:rred irn neari}• .,. ..._ -amste-_ o: . :e t 7.=. ..: - sr.:d:ec, out ... ._:- t::an ~-. ~i .:.e a n.:::ais cf t: _.. io lir.e. Tne r-o:ess was r.D: ~_Jvto:.s. _....,.....~ DCt was an aze-re:ateL c.^.aac° .......... .... __.. _ ..ti.tc..'.= ~.\- = - -ra,..c ... ° . : ai: C`os _Loa- eC ac..:e o- ...rcr.. cr.e•_........._ cr conta:nec ^:etasta:.c .,....,,r of some ::. , car_.r.c::-.a, or leuker:.ic =aere e:e c_id oe as....,__ .., stra:n cr t., t :;._....~ .:c and x. :ables XXV a _ ....~':;. Trachea a::c onc::: - -::e grea: majority of trac: eas and bror.chi from animals o: all groups anc of both strains s=owed no detectable abnormalities. : few ve-: small patches of ^:ild souamous metaplasia were seer. in these passages, slightly more frequently irn the smoke-exposed than in the control ani: :als (columns vi, Tables XXVII through XXX,. Son:e rare scuamo;:s paoillor:as were detected at these sices in smoke-exposed animals, i. e. in 4~o of the trac :eas r*; .,.. of ha*::sters cf t: e ..,. 16 line, and in 2Pc of the tracheas and in 2': c. the bronchi cf : a:r.sters of the 87 . 2C line, but none were seen :.n an•: ef the contrc: a::irr.als (column vii, Tables XXVII through XXX;. ... N W 1 i- ~~?F.1T'P t-~,r ?'c. 0 h~j ~'~'.~ v.' /p R / 1 I / •...' II 2/ ..J^ 3