Gerald Rowley Leighton, The Zoologist (1901)
“ The process, common to all reptiles, of periodically casting off a "slough" is a very interesting one to watch, and can best be observed in serpents. It is not often the good fortune of the observer to be able to see it in natural conditions, though I have encountered several Adders engaged in the act; but in serpents in captivity the whole process can be studied with ease and accuracy. ”
