In Science and Health with Key to the Scriptures Mary Baker Eddy writes (pg. 382)...
He, who is ignorant of what is termed hygienic law, is more receptive of spiritual power and of faith in one God, than is the devotee of supposed hygienic law, who comes to teach the so-called ignorant one. Must we not then consider the so-called law of matter a canon "more honored in the breach than the observance"? A patient thoroughly booked in medical theories is more difficult to heal through Mind than one who is not. This verifies the saying of our Master: "Whosoever shall not receive the kingdom of God as a little child, shall in no wise enter therein."
That got me to wondering, how can a canon ("a regulation or dogma decreed by a church council" according to Miriam-Webster) be more honored by breaching (breaking) it than by following it? To understand this better I looked up the source she is quoting. It is from the play "Hamlet" by William Shakespear. The explanation on enotes is very interesting.
Hamlet is explaining to someone that it is a local custom to drink and carouse late into the night. But he further says that although he's a native of the region he considers it more homorable to break this custom that to follow it.
Mrs. Eddy is pointing out that it isn't wise to obsess over the supposed laws of matter, but to ignore them in favor of the law of God, Spirit. Although she uses the term "hygenic law" she isn't telling us to stop bathing or brushing our teeth. She is telling us not to give these activities power over our bodies... not to fear that omitting to do them occasionally will result in illness.
As I've worked to spiritualize my thought and rise to a fuller understanding of my being as spiritual, it has become painfully obvious to me what a popular custom it is to discuss medical issues in social gatherings. I'm sorry to say that more and more it is making me feel a need to avoid participating in gatherings with my friends. Hopefully I'll reach a point in my spiritual progress where I can be exposed to it without taking it into my consciousness. But as my healing progresses, I really feel I need to avoid conversations about medicine and such.