Hrdlička[43] writes as follows:
My views ... are that any substance which is capable of
producing such effects on the brain and nervous system if
abused is bound to produce harm. Fortunately peyotl is rather
scarce, is used on special occasions only—in a large majority
of cases—and thus it is probably quite free from any permanent
injury.[44] The drug can perhaps be likened to nicotine,
and like the latter will doubtless not affect different
individuals to the same degree. Also, as with nicotine, it
may be quite impossible with our present means to detect the
harm it has done. Besides which it is quite possible that the
system may build up some resistance or safeguard against it and
thus prevent any substantial injury. I should by no means join
myself to those who see in it any _great_ danger.