The author has applied the aluminum cream method for the prepn. of antisera to T. spiralis. This has the following advantages: One injn. of antigen suffices; the rabbit produces antibodies for long periods of time; and the material for injn. need not be sterile. He shows further improvement by means of grinding the organisms when fixed on cream. A high titer antiserum was obtained which was specific for the Trichinella larvae and gave no reactions with any of the host proteins. The work confirms previous observations by other investigators that actively immunized animals can resist infection and the immune serum acts as a prophylactic agent to infection with T. spiralis.