• (1. )
    A description is given of the disintegration and fate of mouse embryos after colchicine injections into the mother.
  • (2. )
    The process is treated in detail for characteristic early and late stages of six- and ten-day embryo age, when the dead tissues remain attached for some time to the uterine wall before breaking up and being discharged, apparently with the oestrous fluid and by the ordinary mechanism of the oestrou.s cycle.
  • (3. )
    There is no evidence of any true re-absorption of the embryo and its associated tissues. A comparison is made with naturally occurring breakdowns, and it is suggested that the process is basically similar but slower and with leucocytes playing a less-prominent part.