AUTOPLASTIC THYMUS TRANSPLANTS : II. WITH PARTICULAR REFERENCE TO THE REGENERATION OF THE RETICULUM CELLS AND THE FORMATION OF HASSALL'S CORPUSCLES.

1. Regeneration of a thymus transplant is characterized by hypertrophy and hyperplasia of the reticulum cells, leading to the formation of small and large atypical Hassall bodies during the early stages. 2. Regeneration is usually complete by the 3rd week, when the newly formed lobules show differentiation into cortical and medullary zones, and typical Hassall bodies appear. 3. Typical Hassall's corpuscles are also derived from the reticulum epithelial cells. 4. These corpuscles have no function, being aggregates of spent reticulum cells. 5. The thymus reticulum cells are actively phagocytic, and react rapidly when noxious influences are exerted on the gland.