Then 20 ml of chloroform was added to each tube and
the contents were again mixed and allowed to stand at
room temperature. After about 2 hr, the suspension was
filtered through a defatted Whatman No. 1 filter paper
and the filtrate and chloroform washings were evaporated
to dryness in a rotary evaporator at 37'C. The evaporator
flask (100 ml capacity) was modified by pushing out
the bottom to form a small cone of about 2 ml volume