Part I. The Investigation of the Clinical Efficiency of Local Anesthetics by Experimental Methods
Criteria of Usefulness.
—The substances that have been introduced as local anesthetics are so numerous that it is difficult properly to compare their value. This has been attempted in a considerable number of experimental investigations; but the results have rather confused than cleared the subject. The confusion is due largely to faulty interpretation and unwarranted extension of the results into fields to which they do not apply, or to the failure properly to analyze and reproduce the essential factors of the clinical use of these agents.The clinical desirability of a local anesthetic is determined on the one hand by its anesthetic efficiency, and on the other hand by the degree of local irritation and by the systemic toxicity.Systemic toxicity has usually been estimated by hypodermic injection into guinea-pigs. The value of this method is