386 



S) TV incklertcc of congested lung m 4 \e%ion »nd » 

 oute ot death wm (unicubrfy freque«M in one 

 |ro«p (10 rrJ) which K»d < hijh mo<iality rate durinf 

 the firtt eiperimenul «ree4s; this Kad 4 nurtcd 

 effect on the number of aninvib «i risic to devek>p a 

 tumour both within arid outs«de the pairMed area or on 

 the irKidence 0/ non-turTX)urous lesiorv irtcrcasir^ with afe 



For comparison with other experiments, additionai 

 •wee of the tame type were treated with pure carano* 

 |er« to esubiish reipomes to defined treatments. 



7) Four calibration groups orif irvilly with 27 mice each 

 were treated with the caror^of en in acetone on the 

 iKived back during 13 or X weeks three times per 

 week, ttartmf at the afe otf 9 weeks. The animak 

 received a toul of OJt or \Sitngof JAbertao- 

 Pr^tne or Ui,i-dibervLBnihraccne and were kept 

 untreated until death occurred tponurteoui^ or was 

 irtduccd in moriburvd arWnak. 



I) Wi the caBbratioo groups (he nymbcr of «iimab bear* 

 inf tumours within the paiixed area was 2} ar^ 27 for 

 *• titn beruopyrenc dosages artd IS and 23 for the two 

 Aeruanthracenc dosac« grot^t. WScn dte Mnour regret. 

 tions were exciuded the number of y^knak involved was 

 21 and 24 for the beruopyrene artd 12 and 21 for the 

 tfberujnthracer^e groups; these resuNi ktdknt dose- 

 ocpcrwcrtoe. 



TTte number of animals bearwg nfubgrwtf lumoun 

 increased with the dosage wtd was 17 and 23 in the 

 two bcnzopyrene groups. « artd 13 in the two dibena- 

 artfhracer>e groups. 



f) A comparison of the results of the batch calibrttion 

 groups between Ciperiments BO and II indicates great 

 similarity for most eiperimenul groups; however, 

 with regard to the 0.78 mg beruopyrerw group the 

 number of aninuh with tumours eiduding rcgressioru 

 increased from Upertment lO to SI from 14 10 21, 

 the number of animals bearirtg malrxnani tumours from 

 f to 17. The validity of companrtg the resufts of 

 different experimenu remaim open to questM^n even 

 ttwugh It was evident in most groups. 



