This monograph is an interesting study by the chief of the hygiene service of the province of Castellón de la Plana. Kala-azar is frequent in Mediterranean countries and especially in the provinces of Spain bordering the Mediterranean. It is essentially a rural infection, and in the majority of instances the presence of infected animals about the patient can be demonstrated. It cannot be entirely established that transmission is by members of the genus Phlebotomus. An excellent bibliography is given.