The thymus as the source of mast cells in the blood.
D000818:Animals; D001773:Blood Cells; D003348:Cortisone / Q000494:pharmacology; D008407:Mast Cells / Q000187:drug effects; D051381:Rats; D013934:Thymectomy; D013950:Thymus Gland / Q000166:cytology* / Q000502:physiology
D003348:Cortisone