This article studies the impact caused by the success and dissemination of Broussais’ theories on the use of leeches as a medical supply on Spanish–French trade relations, as well as its consequences for the Spanish market between 1821 and the 1860s. Analysing the documents produced by the different public administrations, together with newspaper and archival sources in both Spain and France and the literature and legislation of that period, allows us to understand the evolution of this trade and the heavy impact it had on the autochthonous population of this animal resource. The article reveals how, at the beginning of the 1820s, leeches became an important medical supply and how the demand for them increased significantly. This gave rise to a trade relation between Spain and France that led to the overexploitation of the resource, the issuing of regulations on the matter, and the search for technological solutions to increase the production of leeches.

This article explores the relationship between the sent-down youth movement and economic development in rural China during the Cultural Revolution. It examines ways in which sent-down youth themselves initiated improvements in rural life, and more importantly, how local officials used both their presence to acquire equipment and technical training and their skills and education to promote rural industry. The sent-down youth offices established in the cities and the countryside inadvertently provided connections between remote rural counties and large urban centres that enabled the transfer of a significant quantity of material goods, ranging from electrical wires and broadcast cables to tractors and factory machinery. Ultimately, we show how individual sent-down youths, their families, and both urban and rural officials – none of whom had a role in determining government policies – identified and made use of resources that those policies unintentionally produced.