The use of the male Philippine Rana vittigera Wiegmann in the diagnosis of pregnancy

1) Using 780 frogs, we studied the suitability of the male Philippine Rana vittigera as a test animal for the diagnosis of pregnancy2) Of 44 non-pregnant cases, not a single false positive reaction was observed3) Eighty-six known pregnancies in the last trimester were examined. Of these, however, using a 2cc. urine specimen for injections, 3 negative reactions occurred which became positive after the urine from the same cases were concentrated and injected in amounts equivalent to 10 cc. of the native urine4) The earliest age of amenorrhea that gave a positive reaction was 10 days after the first day of the missed menstrual period. (Summary)