In 1907, the Detroit pharmaceutical firm Parke, Davis and Co. purchased property east of Rochester for farms where antitoxins, antiserums, and vaccines were produced using many animals, including horses, cattle, and sheep. During World War I, vital antitoxins for gangrene were produced there, and the company's main pharmaceutical products were vaccines for diphtheria, scarlet fever, tetanus, anthrax, and smallpox. Beginning in 1953, Parke-Davis produced the Salk polio vaccine. Parke-Davis was acquired by Warner-Lambert in 1970, which in turn was bought by Pfizer in 2000. In 2014, Par Sterile Products moved into the site after a series of pharmaceutical corporate acquisitions. The company currently employs 430 people and is the fifth largest generic pharmaceutical company in the country. Parke-Davis was once the world's largest pharmaceutical company and is credited with building the first modern pharmaceutical laboratory and developing the first systematic methods of performing clinical trials of new medications.