To the Editor:—  We read with interest the history of cocaine as a local anesthetic published by Calatayud and Gonzales in the June issue of Anesthesiology. 1We would like to take the opportunity to add few comments to emphasize the role played by Thomas Moreno y Maïz in the understanding of the physiologic effects of cocaine and, even more, its ability to block nerve conduction. Dr. Moreno y Maïz was a Peruvian surgeon who spent at least 4 yr in Paris, where he completed his surgical education. He obtained the degree of doctor of medicine at the University of Paris in 1868. 2Obviously, the nationality and the culture of Moreno y Maïz led him to consider coca as a topic of study. His laboratory experiments, in continuation of physiologic experimentation in animals previously defined by Claude Bernard (1813–1878), may be considered a model of basic research in physiology. They were performed in a variety of animals, including rats, guinea pigs, and frogs. In the first experiments, he described the systemic effects of local anesthetics, including seizures and mydriasis related to the injection of high doses of cocaine. In addition, he observed that the spinal cord remained intact when systemic effects could alter sensibility. In an experiment performed in guinea pigs, he observed paralysis on the side where cocaine was injected subcutaneously. In other studies, he noted the local effect of cocaine in frogs. To separate systemic and local effects, he applied the model used by Claude Bernard to study muscle relaxants, in which one leg was protected by vascular ligature. He demonstrated that the anesthetic effect of cocaine on peripheral nerve was independent of the systemic effects. Then, he injected cocaine into the left lower limb of a frog with isolated heart and isolated right lower limb to suppress the systemic diffusion and observed complete paralysis of the left limb 35 min after the injection. The frog did not remove this limb in response to painful stimulation applied locally or on the contralateral limb. Consequently, Moreno y Maïz wondered on page 77 of his medical thesis, “Could one utilize it [cocaine] as local anesthetic? We cannot state with so few experiments; the future must decide.” More surprising is that these results and considerations remained futile, although the author was already a surgeon in Peru and members of the jury of his thesis were also academic surgeons in Paris. No attempt was made to repeat this first demonstration, at least in other animal models or in humans. Perhaps Moreno y Maïz, more interested by the systemic effects of cocaine, was unable to perceive the treasure under his feet, or perhaps his professional neighborhood rejected his ideas. Moreno’s life thereafter remains largely obscure. Nevertheless, as with von Anrep, 3we should recognize the prime opus due to Thomas Moreno y Maïz.

Hôpital Tenon, Paris, France.

Calatayud J, Gonzales A: History of the development and evolution of local anesthesia since the coca leaf. Anesthesiology 2003; 98:1503–8
Moreno y Maïz T: Recherches chimiques et physiologiques sur l’érythroxylum coca du Pérou et la cocaïne. Paris, Louis Leclerc Editeur, 1868, pp 65–78
Yentis SM, Vlassakov KV: Vassily von Anrep, forgotten pioneer of regional anesthesia. Anesthesiology 1999; 90:890 –5