To the Editor:— My state of incredulity upon reading the report by Deverell and Ferguson of An Unusual Case of Sciatic Nerve Paralysis ( 205 :699, 1968) propelled me to search the literature. This was occasioned by the incidental reference to the administration of a tetanus toxoid booster one week prior to the onset of symptoms. Edsall et al ( 202 :17, 1967) discussed at length many of the problems related to the use of this agent. Blumstein and Kreithen ( 198 :1030, 1966) reported what is believed to be the first recorded reaction of this type. J. L. Garvey ( Postgrad Med 13 :210, 1953) dealt extensively with the various aspects of this problem. R. A. Cooke ( JAMA 114 :1854, 1940) attempt to explain why such reactions occur. It is my feeling that the case reported, might fall into one of these brackets. If this communication serves no more than to call attention