Repressing Disease in Cattle: The Career of Pennsylvania Veterinarian Leonard Pearson

Features appear in each issue of Pennsylvania Heritage showcasing a variety of subjects from various periods and geographic locations in Pennsylvania.
In addition to his many accomplishments in veterinary medicine, Leonard Pearson was state veterinarian (1895–1909), dean of the School of Veterinary Medicine at the University of Pennsylvania (1897–1909), and coinventor of a vaccine to immunize cattle against tuberculosis. University Archives and Records Center, University of Pennsylvania

In addition to his many accomplishments in veterinary medicine, Leonard Pearson was state veterinarian (1895–1909), dean of the School of Veterinary Medicine at the University of Pennsylvania (1897–1909), and coinventor of a vaccine to immunize cattle against tuberculosis.
University Archives and Records Center, University of Pennsylvania

In 1900 there were 224,248 farms and nearly a million dairy cows in Pennsylvania. The livelihood of dairy farmers depended almost entirely on the health of their cows. Dairy cows were vulnerable to a variety of diseases, but the most feared was tuberculosis. In Pennsylvania, bovine tuberculosis killed more cows than any other infectious disease, and it often destroyed entire herds. Bovine tuberculosis was also transmissible to humans through cows’ milk, which caused sickness, and sometimes death, to those who drank it. As a result, an outbreak of tuberculosis among a herd of dairy cows frequently meant an irretrievably damaged reputation and economic devastation for a farmer. None of this was lost on a brilliant veterinary student named Leonard Pearson, who was intent on building a career devoted to the eradication of tuberculosis in livestock and who would one day revolutionize the practice of veterinary medicine.

Leonard Pearson was born on August 17, 1868, in Evansville, Indiana. His father, Leonard Sr., owned a dairy farm and also served as superintendent of the Missouri–Kansas–Texas Railroad. His mother, Lucy Small Jones Pearson, was an educated woman who home-schooled Leonard and his siblings, including sisters Anna and Julia and brothers Raymond, the future commissioner of agriculture in the state of New York, and Edward, who later became vice president of the Missouri Pacific Railroad.

After the death of his father in 1884, Pearson, at age 16, took over the management of his family’s farm in Indiana. That same year, he enrolled in the College of Agriculture at Cornell University, where he spent his summer vacations working to control outbreaks of pleuropneumonia, a contagious and fatal disease in livestock. He then matriculated at the University of Pennsylvania, where he studied veterinary medicine, impressing his instructors with his broad understanding of animals. After graduating in 1890, he decided to go abroad to further his studies, declining an offer of a coveted faculty position at Cornell University’s School of Veterinary Medicine.

In 1891 Pearson traveled to Germany and attended lectures at the Royal Veterinary School in Berlin, where he helped his professors carry out a series of experiments testing for glanders, a deadly disease in horses. Fluent in German, Pearson translated the results of the experiments to English; the findings were published in the prestigious Journal of Comparative Medicine and Surgery. He then spent a year working in the Berlin laboratory of Robert Koch (1843–1910), the renowned physician who discovered the cause of tuberculosis and invented tuberculin, a drug used to diagnose the disease.

Upon his return to the states in 1892, Pearson settled in a Georgian row house on Pine Street in Philadelphia, where he lived with his mother. He accepted a position as an assistant professor at the University of Pennsylvania School of Veterinary Medicine. The boyish, lanky Pearson stood out among his colleagues, most of whom were decades older than him. In 1894, at the age of 26, Pearson was made a full professor. He taught veterinary medicine, supervised students in the surgical clinic and laboratory, and kept daily office hours to tutor students and to interview potential applicants for the veterinary school. Students flocked to his classes, eager to hear lectures presented by the charismatic young professor.

 

The surgical amphitheater at the School of Veterinary Medicine, University of Pennsylvania, circa 1897. University Archives and Records Center, University of Pennsylvania

The surgical amphitheater at the School of Veterinary Medicine, University of Pennsylvania, circa 1897.
University Archives and Records Center, University of Pennsylvania

From then on, Pearson’s rise to excellence in the practice of veterinary medicine can only be described as meteoric. By 1897 he had been appointed dean of the school and was selected to serve as the state veterinarian. He also founded the Livestock Sanitary Board of Pennsylvania and launched a monthly publication, Veterinary Magazine. Over the next few years his list of accomplishments continued to grow: He became president of both the American Veterinary Medical Association and the Pennsylvania Veterinary Medical Association, president of the Guernsey Cattle Club of Philadelphia, and advisor to the State Board of Health. He was a prolific author and wrote dozens of scientific papers and several books, including Special Report on Diseases of the Horse and Diseases and Enemies of Poultry. Colleagues marveled at his “conspicuous ability.”

While he juggled his professional responsibilities, Pearson was also building a private practice, which grew quickly and attracted many wealthy clients. One of his most famous patrons was Walter W. Law (1837–1924), owner of Briarcliff Farms, near the Hudson River in New York. Law maintained one of the finest herds of dairy cows in the country. He insisted on the highest standards of care for his cows and employed a large staff of attendants who fed, bathed and milked each cow twice a day. Barns housing the cows were large, airy and immaculate, and milk was tested daily for bacteria by a chemist at an onsite laboratory, ensuring Law’s commitment to producing the “best and purest milk.” In 1900 Law hired Pearson to oversee the care and treatment of his herd. The two men became good friends, sharing a common vision of the importance of maintaining the health and welfare of livestock.

Despite his commercial success, money was not a motivator for Pearson. He often charged struggling farmers reduced fees for his services and instituted a free clinic at the veterinary school, where the city’s working class could bring their ailing household pets for treatment. He was passionate about horses and volunteered his time at the annual Philadelphia Horse Show.

Despite the demands of his hectic work life, Pearson had a busy social life. Although he never married, he had a large circle of friends and was devoted to his family, particularly his mother, whom he idolized, and his sister, who was fiercely proud of his accomplishments. Pearson also doted on his four bull terrier dogs and was frequently seen walking them through his neighborhood.

 

Bovine Tuberculosis Testing

When Pearson returned from Germany in 1892, he brought Koch’s tuberculin test with him, and he was eager to begin testing it in cattle. His first opportunity came soon, when Joseph Gillingham, a farmer in Villanova, Pennsylvania, suspected an outbreak of tuberculosis in his herd of champion Jersey cattle and asked Pearson to administer the test. Pearson readily agreed and became the first veterinarian in the country to perform tuberculin testing in livestock.

Seventy-one cows were tested, 51 of which were positive for tuberculosis. Pearson knew the disease would inevitably spread to the remaining cattle, and with approval from Gillingham, the entire herd was destroyed. Pearson’s actions aroused the ire of cattle owners, as well as members of the veterinary community. Some cattle owners believed that tuberculin was harmful to their cattle and refused to allow testing. Many people, including some veterinarians, believed tuberculin testing was a sham, because cases of bovine tuberculosis were not always obvious, and cows often appeared to be healthy until they were in an advanced stage of the disease. When public necropsies of the dead cattle were performed, however (drawing huge and vocal crowds), Pearson was vindicated when all the cows were found to be infected with tuberculosis. Furthermore, in December 1900, when he administered the tuberculin test to Law’s herd at Briarcliff Farms, all 1,029 cows were found to be “perfectly healthy,” bolstering Pearson’s campaign for the regular inspection and testing of cattle.

 

The operating room at the School of Veterinary Medicine, University of Pennsylvania, circa 1900. Pearson is seen at work, second from left. University Archives and Records Center, University of Pennsylvania

The operating room at the School of Veterinary Medicine, University of Pennsylvania, circa 1900. Pearson is seen at work, second from left.
University Archives and Records Center, University of Pennsylvania

At the time, farm families lived in fear of an outbreak of tuberculosis among its cattle. There was no cure or remedy for the disease, and infected cows had to be destroyed. The threat of financial ruin encouraged many farmers to accept the importance of testing, and within months Pearson was administering the tuberculin test to some of the most valuable herds in the country. The testing was voluntary; in addition, Pearson lobbied for reimbursement to farmers for livestock that had to be destroyed. In Pennsylvania, a statute was passed authorizing payment of $23 for every lost head of cattle. Eventually, Pearson’s hard work and good will swayed public opinion, and the use of tuberculin became an indispensable tool for detecting and preventing the spread of tuberculosis in cattle.

In 1901 Pearson launched his “Pennsylvania Plan for the Repression of Tuberculosis in Cattle,” a statewide program that called for mandatory testing of cattle, quarantine and disposal of sick animals, and regular inspection of livestock. Education of the public was an important part of Pearson’s plan. At the time, there was widespread belief that human and bovine tuberculosis were caused by different germs. Many scientists also figured that the disease could not be spread from cattle to humans and that consumption of milk and meat from tubercular cows was not harmful. Pearson debunked these myths by gathering and publishing evidence showing that hundreds of people who consumed beef or milk from tubercular cows became infected with the disease, with many cases resulting in death.

Pearson also promoted proper sanitation techniques to keep cattle healthy. Bovine tuberculosis was highly contagious and spread quickly when cattle were crowded together in dark, dirty barns. Pearson personally conducted inspections, advising farmers to expose their herds to fresh air and sunlight and to regularly sanitize stalls and milking equipment.

In 1903 Pearson announced that he and a colleague, Dr. S.H. Gilliland, had developed a vaccine that would immunize cattle against tuberculosis. The news of a potentially preventive vaccine gave new hope to desperate dairy farmers and cattle owners, who had been treating their tubercular cows with homemade remedies, including mashed cocoa beans, cod liver oil, and injections of eucalyptus, in a futile effort to stop the spread of the disease.

 

Diagrams of cattle with tuberculosis from The Effect of Tuberculosis Vaccination Upon Cattle Infected with Tuberculosis (Philadelphia: University of Pennsylvania, 1905), which Pearson coauthored with S.H. Gilliland.

Diagrams of cattle with tuberculosis from The Effect of Tuberculosis Vaccination Upon Cattle Infected with Tuberculosis (Philadelphia: University of Pennsylvania, 1905), which Pearson coauthored with S.H. Gilliland.

Between 1901 and 1903 Pearson tested his vaccine in hundreds of cattle across the state. He kept meticulous records and was able to show that 88 percent of the vaccinated animals were protected from tubercular infection for two years. At the same time, a brilliant German physiologist, Emil von Behring (1854–1917), announced that he had developed an experimental vaccine for tuberculosis, the “bovivaccine,” that would immunize cattle for life. Pearson was dubious and published a letter in the American Veterinary Review stating that Behring lacked the evidence to back his claim. When problems arose with the bovivaccine (several cows died after receiving it), Behring abandoned his work on tuberculosis. (He would go on to invent a serum therapy for diphtheria, which won him a Nobel Prize in 1901.) Pearson continued to improve and test his own tuberculosis vaccine for the rest of his career.

At times, unscrupulous veterinarians performed tests using fake tuberculin and issued fraudulent certificates of health for cattle that were infected with tuberculosis. Pearson was quick to fire dishonest veterinarians when they were caught, noting they “had no place in the practice of veterinary medicine.”

 

Forage Poisoning

Pearson was known for his canny hunches and the depth of his critical thinking. In 1900 he was summoned to a farm outside Philadelphia where five valuable horses had suddenly died. Pearson’s colleague, Dr. Francis Bridge, suspected equine meningitis; Pearson, however, reviewed the horses’ symptoms and behavior and believed there was another reason for their deaths. He carried out a thorough investigation of the horses’ stable, feed and water and found that silage contaminated with mold had been accidentally mixed with the horses’ hay and had also seeped into their drinking water. Pearson fed some of the contaminated feed to two healthy horses, both of which sickened and died after experiencing tremors and paralysis. A necropsy performed on one of the horses showed that the brain and spinal cord were normal, eliminating meningitis as a cause of death. Pearson concluded the horses died of “forage poisoning” and compared the disease to the “sausage and meat poisoning” experienced by humans, a prescient insight, since human food poisoning was poorly understood at the time.

 

Rabies and Anthrax

Although Pearson was passionate about combatting bovine tuberculosis, he also fought other deadly diseases that plagued livestock. In December 1898 Pearson imposed a 60-day quarantine on all dogs in the areas of Baden, Woods Run and Allegheny, where several residents died after being bitten by a rabid dog. In late 1899 Pearson himself narrowly escaped being bitten while examining a herd of rabid sheep in Erie. The outbreak was traced to a rabid dog that ran for miles, biting every animal in its path before it was destroyed. Other outbreaks of rabies continued to rage across the state, and by 1900 Pearson estimated that 300 to 400 cows, sheep and horses had been infected and destroyed. Laws requiring the muzzling and leashing of dogs were enacted, allowing authorities to shoot unrestrained dogs on sight.

Anthrax was another lethal threat. Outbreaks were reported periodically across the state and sometimes led to the deaths of entire herds of cows. To avoid the spread of the disease, Pearson charged the State Livestock Sanitary Board with the difficult task of enforcing the proper disposal of the carcasses of infected animals, burying the remains in a 6-foot-deep trench and covering them with limestone, soil and rocks. Busy farmers sometimes balked at the work and left their dead cattle in fields, allowing the bacteria to spread into the air and soil and trigger new outbreaks. When Pearson learned that the carcass of a cow had been buried by a stream, contaminating the water, he ordered that the animal be dug up and buried properly in a new location. Cattle owners were also permitted to burn the remains of sickened animals. The directions for doing so were quite specific. To completely incinerate the carcass of a 1,300-pound cow took two men five hours and required 5 gallons of kerosene and half a cord of wood.

 

The School of Veterinary Medicine’s ambulance for large animals, circa 1900. University Archives and Records Center, University of Pennsylvania

The School of Veterinary Medicine’s ambulance for large animals, circa 1900.
University Archives and Records Center, University of Pennsylvania

Witchcraft and Crimson Milk

Sometimes the challenges Pearson faced bordered on the bizarre. In April 1902 reports of dying cows on a farm in Kaiserville reached Pearson’s office. He sent an inspector to investigate and was horrified to learn that the owners of the farm, two aging, eccentric sisters named Ann and Louisa Brewer, believed the cows were possessed by evil spirits and had systematically starved them to death. When questioned, the women professed to practicing witchcraft. The county district attorney, George Kyner, ordered them to be held by authorities until their competency to stand trial was determined. The fate of the sisters is unknown.

In another case, a dairy farmer in western Pennsylvania named Stanley Brunges contacted Pearson in a state of panic. During the summer of 1905 Brunges was shocked one morning to see that the milk from his cows was turning a bright red color. Brunges was a major milk supplier in the area and the rose-colored milk was driving his customers away in droves. Pearson went to Brunges’ farm and directed that the milk collected from each cow be kept in a separate tank. He then waited and watched. When he saw that just one cow was responsible for producing the tinted milk, he had her taken to his Philadelphia laboratory for observation. Pearson suspected the color resulted from a bacterial infection in the cow’s udder, though he was never able to prove it.

 

Fake Butter

Throughout the early 1900s, a national controversy raged around the sale of oleomargarine, a butter substitute that was produced by several large food processing companies. At the time, oleomargarine was made of lard and vegetable oils and was easily distinguishable from butter, because of its white color. Trouble arose when unscrupulous manufacturers began to add yellow dye to their oleomargarine and sell it as butter, duping unsuspecting consumers into paying top dollar for the counterfeit product.

When the sale of the tinted oleomargarine began to drive the price of butter down, dairy farmers demanded government action to stop the fraud. Pearson took up their cause, advocating for passage of a bill that would tax the “fake butter.” Speaking publicly at the National Livestock Convention in Chicago in 1901, Pearson declared: “The purpose is not to tax oleomargarine out of existence. It is to tax the fraud out of oleomargarine, sold as butter to people who want butter, ask for butter, and pay for butter.”

Pearson’s activism may have helped the passage of the Grout bill by Congress in 1902. The legislation placed a tax of 10 cents per pound on colored oleomargarine, resulting in a significant drop in the sales of the fake butter.

 

The Battle Against Foot and Mouth Disease

Pearson faced one of his most daunting challenges in early November 1908, when he was called to a farm in Danville, Montour County, to examine a herd of cattle belonging to a man named Jacob Schultz. The cattle were suffering from blistering sores on their gums and feet, which Pearson immediately diagnosed as foot and mouth disease, a highly contagious and often fatal condition that occurred in cows, sheep, goats, hogs and, occasionally, humans. At the time, the cause of the disease was unknown, and there was no cure or remedy. Schultz’s entire herd had to be slaughtered. Milk from his cows was doused with formaldehyde and buried. Despite these efforts at containment, the disease spread rapidly to 14 counties in Pennsylvania.

On November 10, Pearson telephoned the news of the outbreak to the U.S. Department of Agriculture. He then began an aggressive course of action to halt the spread of the outbreak. Traveling back and forth across the state, he inspected, diagnosed and euthanized dozens of infected animals, stopping in towns to educate local veterinarians (some 800 total in the state) about the symptoms and course of the disease. He enlisted hundreds of veterinarians, livestock inspectors and sanitarians to join his cause. It was difficult work that involved isolating and diagnosing sick animals, destroying valuable livestock, performing necropsies, and placating anxious farmers. Untold numbers of railroad cars, barns, stables, water troughs and stockyards needed to be sanitized with chlorine and carbolic acid, a tedious and expensive task that lasted for months. (The disinfection of a single stockyard in Lancaster took two weeks and cost $7,000.) To expedite the task, Pearson invented a portable sanitation tank that could be moved from site to site. In addition, thousands of tons of contaminated hay, corn and other types of feed were burned to slow the spread of the disease.

 

Pearson invented this steam pump to expedite the work of disinfecting farms and stockyards during the outbreak of foot and mouth disease in cattle in 1908. From Leonard Pearson, Report on the Outbreaks of Aphthous Fever in Pennsylvania in 1908–1909 (Harrisburg: Department of Agriculture, Commonwealth of Pennsylvania, 1911)

Pearson invented this steam pump to expedite the work of disinfecting farms and stockyards during the outbreak of foot and mouth disease in cattle in 1908.
From Leonard Pearson, Report on the Outbreaks of Aphthous Fever in Pennsylvania in 1908–1909 (Harrisburg: Department of Agriculture, Commonwealth of Pennsylvania, 1911)

The outbreak was eventually traced to a delivery of infected cows from Buffalo, New York, to Montour County on October 26, 1908. All interstate shipments of livestock between New York and Pennsylvania were immediately banned for six months. Despite the quarantine, thousands of cows, sheep, goats and hogs had to be destroyed, bringing economic devastation to farmers, merchants and shipping companies. Twenty-five farmers across the state lost their entire herds, and hundreds more were left without their livelihoods for months. Throughout the crisis, Pearson kept meticulous records detailing the location of each outbreak, the types and numbers of animals affected, and appraisals of the value of lost livestock.

The outbreak was not confined to animals. Four children in the Danville area contracted the disease by drinking raw milk from infected cows. The children recovered; however, a child in New York state who contracted the disease died. After the outbreak, physicians redoubled their efforts to educate the public about the need to boil milk before drinking it.

 

Failing Health

By the spring of 1909 the outbreak was contained, and the quarantine was lifted; however, the toll the crisis had taken on Pearson’s stamina was apparent. Battling fatigue and insomnia, he was often seen dozing at his desk by coworkers. On June 9, while preparing tea for his sick mother, Pearson fell asleep, unaware that the flame on the gas stove had gone out. Toxic gas filled the room, rendering both Pearson and his mother unconscious. Servants checking on Pearson’s mother discovered the comatose mother and son and rushed them to University Hospital, where they were treated with oxygen. Pearson’s mother did not respond well to the treatment and required a transfusion of blood, which was donated by Pearson’s close friend and fellow veterinarian, Dr. C.J. Marshall. Although both Pearson and his mother recovered, Pearson never regained his strength and vitality, and he was forced to periodically take time away from work to rest.

In 1909 Pearson decided to take a much-needed vacation. He loved the ocean and embarked on a cruise in July to Savannah, Georgia, and then to England. During his return trip he stopped in Halifax, where he was struck with a severe bout of hay fever. On the advice of his physician, Pearson went to Newfoundland, where the climate was believed to be beneficial to allergy sufferers. He stayed for several weeks at the Log Cabin at Spruce Brook, a large and comfortable inn overlooking a pond. His health seemed to be improving, and he wrote to his staff in Philadelphia that he hoped to be back to work soon. But Pearson would never return to his office; he died suddenly on September 30, 1909, at age 41. The cause of his death was believed to be a heart attack.

News of Pearson’s death was shattering to his friends and students. At his memorial service, dozens of colleagues and officials eulogized him. The memoriam published in his honor ran to over a hundred pages and included heartfelt tributes: “If any more lovable man has lived, I have not made his acquaintance,” said one colleague. Another noted: “His death is a loss to science and a blow to the uplifting of mankind. A few men of his type could leaven the world.”

At the time of his death, Pearson was overseeing the completion of new buildings for the School of Veterinary Medicine that would house a surgical suite with multiple examination and operating rooms, an auditorium, and a library. University faculty members were unanimous in their decision to dedicate one of the buildings to Pearson’s memory. A plaque commemorating Pearson was donated by the Guernsey Breeders Association and now hangs outside the Leonard Pearson Hall, the site of the Pearson Memorial Library.

Pearson’s list of achievements is staggering. In addition to combatting bovine tuberculosis and other deadly veterinary diseases, he established sanitation standards for slaughterhouses, developed guidelines for meat inspection, helped broaden the curriculum for veterinary studies, improved veterinary surgical techniques, and translated dozens of scientific papers from German to English.

Today, Pearson’s legacy is honored by the Leonard Pearson Veterinary Prize, which is given annually at Cornell University to the fourth-year veterinary student who exhibits the greatest potential for achievement in the field of veterinary medicine.

 

Further Reading

Blossom, Mary C. “The New Farming and a New Life.” The World’s Work: A History of Our Time 3 (November 1901 to April 1902): 1626-1637. / History of the School of Veterinary Medicine of the University of Pennsylvania, 1884-1934. Philadelphia: Veterinary Alumni Society, University of Pennsylvania, 1935. / Law, James, Veranus A. Moore, and Simon Henry Gage. In Memoriam: Leonard Pearson. Philadelphia: University of Pennsylvania, School of Veterinary Medicine, 1910. / Melvin, A.D. “The 1908 Outbreak of Foot and Mouth Disease in the United States.” In: U.S. Department of Agriculture. Twenty-Fifth Annual Report of the Bureau of Animal Industry for the Year 1908. Washington, D.C: Government Printing Office, 1910, pp. 379-392. / Pearson, Leonard, and M.P. Ravenel. Tuberculosis of Cattle and the Pennsylvania Plan for Its Repression. [Harrisburg, PA]: Commonwealth of Pennsylvania Department of Agriculture, 1901. / “Report of the State Veterinarian.” In: Annual Report of the Pennsylvania Department of Agriculture 1903. Harrisburg, PA]: Commonwealth of Pennsylvania Department of Agriculture, 1904, pp. 102-105.

 

Mary Franz is a freelance writer who lives and works outside of Boston. She grew up in western Pennsylvania and loves writing about the state’s colorful past.