A morphological study of the ultimobranchial body in the grass parakeet.

As parafollicular cells can be stained by Grimelius' silver impregnation and by lead-hematoxylin, the ultimobranchial body cells, homologous to them, seem to also react positively to these methods. In the present study of the ultimobranchial body of the grass parakeet, mirror-image sections were stained by both methods and compared. While about 50% of the cells reacted positively to both Grimelius' silver impregnation and lead-hematoxylin staining, only about 20% were positive to the former and about 30% were positive to the latter only. This result indicating heterogeneity among the cells of the ultimobranchial body of the grass parakeet suggests a possible occurrence of cells secreting substances other than calcitonin.