He suggests it only when drug therapy fails to work.

VOA: special.2010.02.17

I take it that we all agree that when we attempt to run the Cartesian argument in terms of the Morning Star and the Evening Star, it fails. But it's harder to say what went wrong?

我想大家都同意,当我们试图把卡氏论证,用到晨星和昏星的例子上来时,它行不通了,但是很难说我们哪里错了

耶鲁公开课 - 死亡课程节选

It's a virulent strain that occurs when a person with TB fails to complete the six to nine-month course of medication or catches TB from another person who is ill with a drug resistant-strain.

VOA: standard.2010.07.12