Universlty of Manitoba, ln Partîal Fulfiìlment - MSpace at the ...

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5,3.2 Pa-rôf i Idì ¿irid PIèsticIrie l,Jìthoút 1^1î ridoli,î n9
Chemical agents ¡n the plasticÌne or parafi lm used to seal rv i ndowed
eggs, rather than vîbratîon by the dental disc, might alternatîvely be
responsible for the teratogenîc effect of windowlng. This possibil ity
was tested by applylng a parafílm circle and.plasticìne ring to the
intact shell overtylng three groups of embryos.
Eggs were first candled to locête the postion of the embryos,
and the plasticîne,/parafl lm covers applìed at 0,26, and 33 hours of
incubation. Embryos were recovered after a total of / days.
Tables 12 and 13' show that the mortal ity and overall malformation
rates are lowest ln the control group and hlghest in embryos treated
from the begînning of incubation. Because of the smaìl numbers in each
group values are not converted to percentages. The results, however,
show that there ls no obvious teratogenic factor emanatîng from the parafilm/
plasticlne covers alone. ln the control group there was onu ,pont"nou,
open cord defect.