The presence of argyrophilic granules in the parenchymal cells of the parathyroid glands.

@article{Weymouth1954ThePO,
  title={The presence of argyrophilic granules in the parenchymal cells of the parathyroid glands.},
  author={Richard J. Weymouth and B L Baker},
  journal={The Anatomical record},
  year={1954},
  volume={119 4},
  pages={519-27}
}