The image below appears in Radiohead.com‘s Scrapbook section.
It reads (approximate):
–the hair of the dog
when you can’t recognize
a Dog of wolf
This early print of “Le Chien-Loup” is by Georges-Louis Leclerc, Comte de Buffon (1707-1788). There is a book entitled Le chien-loup by Jean Ferniot. There is also an extensive web site on the breed, one with an interesting history: “In the year 1955 a biological experiment took place in the CSSR of that time, namely, the crossing of a German Shepherd Dog with a Carpathian Wolf.” Reader andres bisserier suggests the phrase “when you can’t recognize / a Dog or wolf” may mean “something like ‘when you can’t tell if it’s a threat.'”