Abstract

1. There is no foundation for the statement that double adrenalectomy in rats causes them to become 400 to 500 times more sensitive to morphine than normal animals. There is, indeed, no evidence that any significant change in tolerance occurs.

2. Most of the deaths, resulting from double adrenalectomy in rats, occur within a period of about ten days, beginning toward the end of the first week following the operation.

3. Tests for tolerance of depressing drugs or potent bacterial toxins can not yield reliable results if made during this period of high mortality in adrenalectomized rats.