Understanding the Process of Animal Testing

Sulfanilamide was quite the wonder drug—at least it was in the early 1900s.

As an antibiotic, sulfanilamide was widely used to treat various infections. People typically took it in powder form, but in 1937, the Tennessee-based S.E. Massengill pharmaceutical company recognized the demand for the drug in a liquid version. Chemist Harold Cole Watkins experimented in the lab, discovering that sulfanilamide dissolved well into diethylene glycol. They added raspberry flavor, tested it for taste, appearance, and aroma, and gave it a seal of approval. They called it Elixir Sulfanilamide, and soon S.E. Massengill began mass-producing it, sending out 633 shipments nationwide that September.

However, on October 11, doctors in Tulsa, Oklahoma, alerted the American Medical Association (AMA), expressing concerns that the new elixir wasn't healing—it was causing deaths. The AMA tested a sample, and while the sulfanilamide itself was safe, the issue was the diethylene glycol. This substance wasn't just harmful; it was a deadly poison, causing excruciating agony and death to its victims.

The Food and Drug Administration quickly took charge, launching a nationwide campaign to raise awareness and dispatching inspectors across the country to track down every last drop of the deadly liquid responsible for claiming over 100 lives across 15 states.

At this point, modern readers can't help but be astonished and ask: How? How did this happen? How could a pharmaceutical company think a deadly poison was suitable for an antibiotic? Clearly, Watkins overlooked crucial research. There were studies already available that showed the toxic effects of diethylene glycol. He had neglected them. Mistakes do happen, but that’s why we have safeguards. That’s why we conduct rigorous testing, particularly for medications.

Ah, but here’s the catch. The only tests S.E. Massengill performed on the elixir were for flavor, scent, and visual appeal. They never bothered to check if it might actually be fatal. Why? Because they didn't have to.

In fact, the company’s president defensively responded to the accusations, arguing that while the tragedy was unfortunate, S.E. Massengill had done nothing wrong. However, Watkins seemed to feel differently, as he tragically took his own life [source: Ballentine].

In 1938, the U.S. Congress passed the Federal Food, Drug, and Cosmetic Act, which, among other provisions, mandated that all new drugs undergo animal testing before they could be approved for sale to the public.

Testing, Testing, 1, 2, 3

In second-century Rome, the distinguished Greek physician Galen was preparing to perform a public demonstration of one of his groundbreaking discoveries. At a hall rented for this purpose, a restrained pig was brought in, and Galen proceeded to explain to the gathered audience of intellectuals how he would demonstrate that animals possess something called nerves, which control everything, including the voice. He claimed that by making a small incision to the right nerves, he could silence the pig without causing it harm.

Before Galen could proceed, however, a philosopher named Alexander Damascenus raised an objection, arguing that even if the pig stopped squealing, it would not prove that humans have a similar nervous system. He further contended that demonstrations were futile; Galen's assertion could not possibly be true.

This was the kind of challenge that Galen, along with anyone else relying on the scientific method, faced. Greek and Roman philosophy at the time maintained that seeing wasn't necessarily believing. Empirical evidence was often dismissed in favor of logic and established doctrines. Aristotle believed that the heart, rather than the brain, governed all thinking and speech, and for many philosophers, his views were considered irrefutable. Galen's experiment wouldn't convince Damascenus or others who held to Aristotle's authority.

Galen stormed out in frustration, declaring he wouldn't waste another moment on such ignorant fools (or something along those lines). His audience quickly rallied against Damascenus, urging Galen to proceed with the experiment. Galen agreed, and the demonstration with the squealing pig left everyone in awe, marking one of the earliest known instances of animal experimentation for scientific purposes [source: Gross].

Well before Galen, in the fourth century B.C.E., Aristotle had conducted some live-animal testing, though the results were far from perfect. Soon after, another early Greek physician, Erasistratus, took up animal experimentation as well.

In 12th-century Moorish Spain, the Arab physician Ibn Zuhr, also known as Avenzoar, applied some of his pioneering surgical techniques on animals before attempting them on humans [source: Hajar]. Naturally, this occurred long before the advent of anesthesia, so both the animals and humans endured a painful experience.

In the 19th century, French physiologist Claude Bernard (widely regarded as the father of physiology) championed animal testing to such an extent that it became a cornerstone of the modern scientific method. While many, like Damascenus, believed that the physiology of animals like pigs had no relevance to humans, Bernard demonstrated that vertebrate mammals were remarkably similar to humans, making animal testing crucial for advancing human health [source: Hajar]. And human health, at the time, was in dire need of improvement.

A chilling scene in the "Little House on the Prairie" series recounts how the Ingalls family nearly perished from malaria after being struck by a mosquito infestation. In the 1870s, as settlers like the Ingalls family moved to the Midwestern U.S., the common belief was that diseases like malaria were caused by everything from "damp air" to watermelons. No one knew that the true culprits were microscopic, blood-borne bacteria carried by mosquitoes.

In the late 19th century, German microbiologist Robert Koch examined blood samples from cows that had died from anthrax. Under the microscope, he observed strange bacteria, which he hypothesized could be the cause of the disease. To confirm his theory, he injected some of the cow's blood into mice, and sure enough, the mice contracted anthrax as well. This groundbreaking experiment revolutionized the field and paved the way for Louis Pasteur's germ theory of disease [source: NAP].

Animal testing had already proven to be valuable in scientific research. A few decades later, the Elixir Sulfanilamide tragedy would make it a mandatory part of the drug development process.

Testing Today

In 1957, Russian geneticist Dmitry K. Belyaev had a bold idea. He wanted to see if he could replicate the domestication of dogs with a different species. Humans had spent thousands of years selectively breeding dogs to tame them. Could Belyaev achieve the same result with foxes in just one human lifetime?

Belyaev traveled to Siberia, where he gathered silver foxes raised for the fur trade, and began his groundbreaking experiment. With each new litter, he tested the fox kits for their temperament, selecting only the calmest and gentlest for breeding, while the others were euthanized. After 25 years and 20 generations, the result was tame foxes that were friendly enough to be kept as pets. Fascinatingly, as the foxes became more docile, their tails shortened and curled, their ears flopped, and their fur developed spots. This simultaneous change in both behavior and physical traits is called domestication syndrome, and studying this process has led to important insights into evolutionary biology [source: Newman and Craig].

The silver fox experiment is a notable example of animal testing in behavioral research, similar to Pavlov's renowned dog experiments. These represent just a few of the countless ways in which animals are used by scientists to explore a wide variety of questions.

A significant portion of evolutionary biology research is conducted using organisms like fruit flies and tiny nematode worms, chosen for their fast reproduction rates and ease of breeding. For example, researchers often use nematodes such as C. elegans to test antibiotics by infecting a group of worms with a disease and then exposing a control group to a potential antibiotic to observe which survive [source: AnimalResearch.Info].

In disease research, the animals used depend on which species are vulnerable to specific conditions. For example, Armadillos are the only animals besides humans known to contract leprosy, also called Hansen's disease. Their body temperature is ideally suited for harboring the M. leprae bacteria. This unique trait has led scientists to use armadillos in studies to better understand leprosy and to develop experimental vaccines [source: AnimalResearch.Info].

Rats are commonly used in laboratories, but mice are even more prevalent due to the fact that their genes share a remarkable 90 percent similarity with ours. Additionally, their cellular structure and organ organization closely resemble those of humans. Much of the research involving mice revolves around breeding and genetic modification, often paired with behavioral studies that include memory tests and navigating mazes.

Cats are often chosen for neurological research because of their advanced sensory abilities, including keen hearing, vision, and balance. Meanwhile, dogs, particularly the calm and gentle beagle, are subjects of biomedical studies exploring ailments like prostate cancer and muscular dystrophy, as they share these conditions with humans. Dogs are also commonly involved in drug safety testing, often after preliminary tests on mice.

Non-human primates, especially macaque monkeys due to their large and widespread population, are also key subjects in research. Despite a significant decline in primate studies in recent years, these animals remain essential for research on brain disorders like Alzheimer's, as no other species possesses brains as similar to humans as these primates [source: Oxford University].

Getting Testy

Throughout the 20th century, human life expectancy consistently increased by about three months each year. Proponents of animal testing attribute much of this remarkable growth to animal experimentation. They argue that the medical advancements we rely on today, such as antibiotics, vaccines, surgeries, and cancer treatments, would not be possible without it. For this reason, advocates maintain that animal testing must continue to drive further medical progress. They emphasize that more than half of the diseases affecting humans today still lack effective treatments [source: Oxford University].

However, many are opposed to animal testing. Groups like People for the Ethical Treatment of Animals (PETA) believe that conducting experiments on living creatures who cannot consent is unethical, harmful, and wasteful. They highlight the significant suffering of animals involved in scientific research, arguing that such pain is often unnecessary.

Critics argue that despite successes in animal models, such as curing cancer in mice, these treatments rarely translate to human trials. The same holds true for the 85 HIV/AIDS vaccines that showed promise in primates but failed in humans. One vaccine may have even made people more susceptible to the disease. The U.S. Food and Drug Administration acknowledges that the majority of drugs in development fail in human trials after early animal testing, as animal models do not accurately predict human responses [source: PETA].

On the other hand, the scientific community generally agrees that animal testing is still both valuable and essential. Experts argue that there is no real substitute for the biological complexity found in living organisms. Since we do not fully understand all the factors that contribute to an organism's functions, it remains impossible to predict how a drug, for example, will interact with the various bodily systems.

Experimental Experimenting

The ethical concerns surrounding animal testing have been debated for as long as the practice has existed. Even Charles Darwin, a key figure in the study of animal physiology, voiced his opinions on the matter. While Darwin strongly supported the study of animals, he also emphasized the importance of their humane treatment.

In 1874, four scientists were tried for cruelty after performing a gruesome experiment on dogs. During this demonstration, the animals were cut open and infused with alcohol and absinthe to observe their effects on the nervous system, all without anesthesia. Although the accused were acquitted, the trial brought widespread attention to the animal testing controversy.

While some activists called for a complete ban on animal testing, including vivisection, Darwin joined forces with more moderate campaigners in the U.K. to draft legislation that would regulate the practice. His efforts contributed to the creation of the Cruelty to Animals Act of 1876 [source: Johnson], which aimed to protect animals from unnecessary suffering during scientific experiments.

Animal testing regulations have continued to evolve over time. In 1954, the Universities Federation of Animal Welfare sponsored young scientists William Russell, a zoologist/psychologist, and microbiologist Rex Burch, to investigate the state of animal testing and propose improvements to its practices.

In 1959, Russell and Burch introduced a pivotal concept in animal testing, which has since become central to humane practices. This concept, known as the 3Rs, stands for replacement, reduction, and refinement. The principle suggests that researchers should first attempt to replace sentient animals with non-sentient alternatives; if replacement is not possible, they should reduce the number of animals used to a minimum; and lastly, they should refine their methods to minimize animal suffering as much as possible [source: Flecknell]. The 3Rs form the foundation of the Animal Welfare Act and are adhered to by researchers not only for ethical reasons but also because they enhance the quality of scientific research.

While both animal-rights groups and pro-animal testing scientists can agree on the importance of the 3Rs, organizations like PETA argue that more should be done to replace, reduce, and refine animal testing. They point to studies showcasing the superiority of alternative methods, such as using human volunteers, advanced computer simulations, and in-vitro human cells and tissues. These alternatives, they claim, have been proven to yield more accurate results than traditional animal-based testing.

Supporters of animal testing argue that while alternative methods are valuable, they haven't yet replaced all animal testing processes. In some cases, in-vitro tests and computer models cannot fully substitute for real biological systems [source: Oxford University].

The debate surrounding the use of animals in research continues, with public opinion divided on the matter [source: Pew]. Advocacy groups pushing for animal rights and the implementation of the 3Rs have led to a gradual decrease in the use of certain animals, particularly primates, in experiments [source: Oxford University].

People who believe animals should be treated humanely yet fear that banning animal testing might hinder scientific progress face a dilemma. To justify animal testing, we must assume that human lives hold more value than those of non-human animals. While this belief is widespread, it is rooted in bias, not fact. But, as humans, we are inherently biased—there’s no need to test that truth.