Experimental puffs in salivary gland chromosomes of Drosophila hydei

Summary In Drosophila hydei abnormal puffing activities could be induced by temperature shocks and treatments with 1.2% and 1.4% KCl solutions. After temperature shocks in vivo and in vitro, a number of puffs showed a similar change in activity.Other puffs were found to show a change in activity only after a distinct treatment.Some of the puffs, specific for temperature shocks, showed a change in activity only at a distinct stage of development.In discussing the results, particular attention is paid to puffs observed in common after all treatments.Dedicated to Prof. H. Bauer on the occasion of his sixtieth birthday.