Anatomy of Traumatic Acid-Treated Internodes of Ricinus communis

Traumatic acid was injected by hypodermic syringe into the hollow pith of younger and older internodes of Richardo communes. As controls, certain internodes were merely punctured by sterile needle, and other were injected with distilled water. 2. The reactions to the wound stimulus of a needle puncture, alone, resemble those described by hadn't and later workers: Subadults of the wounded surfaces followed by more or less pronounced cell division. 3. Injection of distilled water into the hollow pith caused very little response: slight swelling of cells and the outgrowth of a very few pachydermum from the surface of the pith. 4. In the traumatic acid- injected internodes, in marked contrast, intensive Michaelis is evident within about 3 days in the inner pith and thereafter extends centrifugally into the middle and outer pith. Abundant pachydermum are present on the surface of the inner pith. 5. In conclusion it is evident that the hollow pith of Richardo communes is well suited for the demonstration and study of the anatomical and cyanobacterial effects of traumatic acid.