The occurence of Psammom bodies in the thyroid gland of aged rats]

The author examined the thyroid glands of 52 aged (18 to 30 months old) and 14 young (6 months old) male rats with histophysiological methods. By means of light-microscopical examinations he observed laminated colloid, i.e. psammom bodies which contained calcium and iron, in the follicles of the thyroid glands of the old rats. Founding himself upon data of the literature, he deals with the questions of the occurrence and origin of the psammom bodies. Relying on his own examinations he is of the opinion that in the case of animals involution and dystrophic of a certain degree connected with senescence calls forth on oedema which and besides also the adenomas occurring in greater numbers means a disorder of the metabolic processes taking place in the thyroid gland and a possibility of the formation of psammom bodies. Eventually, in the authors opinion it cannot be stated with certainty -- at least in the case of animals -- that there is a close relationship between the occurrence of psammom bodies and the neoplasma.