“…The evidence for circulating antibodies reported by most investigators was obtained with heterologous antigens used to evoke demyelinating antibodies [6,7], hemagglutinating antibodies [12], non-precipita ting antibodies [13,23], PCA-reacting antibodies [45,51] and gelprecipitating antibodies [4,[15][16][17]49,50]. Some investigators [15,49] used purified preparations of heterologous BP and found no evi dence of species specific contaminants, but they had no homologous antigens for comparison.…”