Abstract
Repeated skin tests with 0.1 ml. of undiluted histoplasmin, blastomycin or a 1-10 dilution of heat-killed yeast-phase antigens of Histoplasma capsulatum and Blastomyces dermatitidis may sensitize normal guinea plgs. Histoplasmin and blastomycin, diluted 1-10 or 1-100, did not sensitize. Similar results were obtained with an autoclaved filtrate from Candida albicans. A heat-killed suspension of C. albicans sensitized at a dilution of 1-100.