1. Physiological elastic deflection of the hyalin cartilaginous part of the acetabulum can be separated from real instability signs.

2. Acute regressive alterations are initiated by haemorrhages and sero-fibrinous deposits. They can be transformed into cystic lesions or undergo organisation with formation of hyalin scars with haemosiderin deposits.

3. In addition to amyloid degeneration in their walls typical of Alzheimer's disease the brain vessels showed hyalin degeneration of the media, vascular stenosis and occlusions, miliary aneurysms as well as old and fresh hemorrhages.

4. The archenteron morphologies displayed in the 30 replicates (×3 controls) were 94 ± 6% complete Archenterons and 4 ± 0.7% unattached Archenterons in the combined control samples and 8 ± 1% complete Archenterons and 83 ± 6% unattached Archenterons in the hyalin-treated samples (30 replicates).