Abstract: In order to take a practically unlimited number of fluid samples, in particular from a well in production, a sonde is used including as many modular sampling devices (10) as there are samples to be taken. These devices (10) are disposed end-to-end and they are actuated in succession by a central control rod (66 ) driven back-and-forth by an actuator device situated at the top end of the sonde. A bottom end piece puts the bottom sampling device into a ready position in which it is ready to be actuated by raising the rod (66). By taking a sample in this way, the bottom sampling device also serves to put the adjacent sampling device into its ready position, and so on all the way up to the topmost sampling device.