How Free Does the Will Need to Be?

This is the text of The Lindley Lecture for 1985, given by Bernard Williams (1929-2003), a British philosopher

Studies on the epizootiology of canine cestodes particularly Taenia multiceps and ovine coenurosis

In a survey of 552 sheep flocks in Dyfed, Wales, carried out in 1973, coenurosis occurred in 375 (68%) with an estimated average annual flock incidence of between 2.5 and 3.0%. Evidence of infection with the larval stage of Taenia multiceps was found in 58/1000 (5.8%) lambs sent for slaughter. Taenia multiceps was recovered from 37/320 (11.5%) dogs on 20/100 sheep breeding farms, 3/39 (7.7%) dogs on 2/18 sheep wintering farms and 41/552 (7.4%) hounds in 4/12 packs. The frequency of cestode infection in farm dogs and hounds was closely associated with the feeding of uncooked meat and offal and the absence of regular anthelmintic treatment. Only one (0.6%) of 166 pet dogs and one (0.26%) of 387 foxes examined harboured Taenia multiceps and neither were considered to be of importance in the epizootiology of Taenia multiceps. Dogs were experimentally infected with Taenia multiceps and remained infected for up to periods of six months or longer, and up to 21 proglottids were shed each day. Rabbits and mice could not be experimentally infected with oncospheres of Taenia multiceps, but lambs which were experimentally infected with the oncospheres developed acute or chronic coenurosis. Suspensions of oncospheres in distilled water remained viable at 3 - 11°C for periods up to eight weeks, but the coenurus was viable for no longer than four days in the intact skull at 9 - 11°C. The pathogenesis of acute and chronic coenurosis, with particular reference to the clinical signs, clinical pathology, pathology and immunology, was studied in experimentally infected lambs and selected field cases of the disease