John Mckiernan-González, assistant professor at the University of Texas at Austin, tackles a daunting list of topics in Fevered Measures, including race, ethnicity, national identity, shifting borders, the meaning of citizenship, and state formation. Using a series of case studies, the author demonstrates how political borders and medical borders did not always coincide. Medical borders could change depending on the health threat involved and the framework within which health officers approached it. There was no guarantee that this new medical boundary would correspond to the existing international boundary.The author begins by defining the various political, ethnic, and racial labels that were used to describe people: American, Anglo, Mexican, Mexican American, and Tejano, to offer only a partial listing. He also furnishes some background medical information on the diseases that will play such an important role in the unfolding of his narrative: smallpox, typhus, typhoid, cholera, and yellow fever. It was the public health officials who determined the medical border, the line drawn to protect American citizens. As a result, public health policies played an important role in establishing national identity. Public health officials, especially officers of the federal US Marine Hospital Service (USMHS), converted medical authority into political authority through their ability to control the flow of traffic in the border region.Professor Mckiernan-González’s first case study involves the US-Mexican War of 1846 – 1848. The military victories of the United States in the war were almost undone by the medical problems the country’s army experienced, which led to a high death rate among US forces. After civil war in Mexico and the United States in the 1860s, public health concerns became a part of the national reconstruction plans of both nations. The USMHS received the power to develop policies to meet epidemics, implementing its first military quarantine in response to an outbreak of yellow fever in Brownsville, Texas, in 1882. The quarantine involved the creation of a 190-mile-long quarantine line stretching from Laredo to Corpus Christi, effectively putting a large part of South Texas outside America’s medical boundaries and giving control over movement across the Rio Grande to the USMHS. The area quarantine seemed to confirm in the minds of Ameri-cans that Mexicans posed a medical threat.The attitudes of American medical authorities toward quarantines, of which they initially disapproved, changed dramatically in the decade after 1882, when quarantines were made a central feature of government plans. Quarantines had become a means of asserting state sovereignty. Quarantines along the Texas-Mexico border once again emphasized the problem of distinguishing between Mexican as a basis for national citizenship and Mexican as referring to an ethnic community in Texas. Reformers in the late nineteenth century were increasingly concerned about how public health fit with social justice.One of the case studies that receives extensive coverage from Mckiernan-González is that of American colonists moving to Mexico. A group of African Americans were to move from Alabama to work with the Tlahualilo Agricultural Company in northern Mexico as sharecroppers. The colonists had been misled about the conditions that they would operate in and rebelled at the treatment they were receiving from the company. They also demanded that the US government intervene to help them. The situation became even more complicated when smallpox broke out among the colonists, leading American public health officials to assert their medical sovereignty in the case. The US government came to the rescue of the colonists. When the colonists arrived in Texas, state officials placed all of them under quarantine. Texas officials later turned the colonists over to federal officials, who used them as research subjects in testing a smallpox antitoxin. The Tlahualilo intervention expanded the concept of quarantine and once again clearly demonstrated that the medical border did not necessarily coincide with the political border.One of the most spectacular case studies in this text involves the smallpox riot in Laredo in 1899. When public health authorities attempted to implement a program of vaccination and fumigation, there was strong local resistance. Opposition to the program eventually led to the involvement of the Texas Rangers and US Cavalry. While some considered vaccination as evidence of the modernization taking place on both sides of the border, others resisted forced vaccination into the 1940s.Professor Mckiernan-González demonstrates how public health activities helped to create a new sense of nationhood and changed the idea of disease in the Texas-Mexico borderlands. Drawing upon extensive archival resources in both the United States and Mexico, he provides a different way of approaching racial, cultural, and even diplomatic relations in the borderlands. Fevered Measures will make an excellent addition to such works as Amy Fairchild’s Science at the Borders: Immigrant Medical Inspection and the Shaping of the Modern Industrial Labor Force (2003) and Continental Crossroads: Remapping U.S.-Mexico Borderlands History (2004), edited by Samuel Truett and Elliott Young.