In this paper the author examines the geographical and familial origins of Dr. Tholozan which contributed to the orientation of his career and future preoccupations. To begin, he evokes a first cousin of his father: Dr. Andre Francois Cauviere (1780-1858), a well known personality in Marseille, whose family originated from the Var department and whose influence on Tholozan seems to have been decisive. The Tholozan themselves came from a village near Embrun (Hautes-Alpes) where they were craftsmen and merchants. Tholozan's father married in Toulon a miss Amic. Her family included various tradesmen settled overseas. It is probably these familial relations which incited the couple to sail to the Indian Ocean. There, six years after his parents' marriage, was born Joseph Desire on the tiny atoll of Diego Garcia, a remote dependency of Mauritius. Later his family having returned to Marseille to live there, it is in this city at the side of Dr. Cauviere who distinguished himself during the cholera epidemics that the future physician will carry out a part of his medical studies before ending them in Paris.