The author, formerly a surgeon in the Peruvian army, issued the first study of the pharmacological action of cocaine, containing the earliest suggestion of its use as a local anesthetic. Leclerc issued the commercial edition of this thesis for the doctorate in medicine at the Faculté de Médecine in Paris. The thesis edition of this work, with a different title page, and perhaps other printing differences, was published by A. Parent, Imprimeur de la Faculté de Médecine, also in 1868.

"Obviously, 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...." (Emmanuel Marret , Marc Gentili, Francis Bonnet, "Moreno y Maïz: A Missed Rendezvous with Local Anesthesia," Anesthesiology, 100 (2004) 1321-1322) .