The Reactions of Isolated Parts of Spirostomum

Abstract

1. Spirostomum shows differential responses to localized mechanical and chemical stimuli. 2. The entire body surface is sensitive to mechanical, chemical and thermal stimuli. 3. The spiral path followed during swimming is due to the co-ordinated activity of the body cilia. 4. Immediately after isolation, fragments do not behave like normal animals, but respond with reference to the position they occupied in the whole organism. 5. When morphological regulation is complete, the responses of the fragments are normal. 6. As revealed by the study of the responses of fragments, Spirostomum is not organized like a crystal, but seems to have a definite gradient pattern.