How did animal experimentation become so established to begin with?
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However unreliable, subjecting animals to experiments for which humans would never volunteer has immeasurable plusses, evident throughout time. Animals cannot dissent.

There have always been abundant human bodies, tissue and blood to illumine our knowledge base. However, in the West, Christianity pervaded, and papal decree forbade autopsy. During the second century AD, a Roman physician named Galen performed endless animal experiments to inform his over-500 treatises that drew conclusions about human physiology. Many of these conclusions were entirely faulty and contributed to the "darkness" we now associate with medieval times, during which powerful Church officials continued to frown on autopsy.

The Renaissance offered a slight reprieve. Competitive intellectual inquiry emerged to overwhelm Church injunctions. Autopsies revealed medical inaccuracies that had prevailed for 1,300 years since Galen. They began to cast light on real causes of disease.

In the mid-nineteenth century a man who had failed as a playwright, Claude Bernard, took up animal experimentation. His tremendous zeal and the sheer volume of results - accurate or not - that issued from his subjugation of animals effectively created an animal experimentation business. Medical research would henceforward extend beyond the purlieu of physicians; people who could not make it as doctors could still make a living as animal experimenters, as well as wield wide influence. In fact, the machine of animal experimentation generated such an abundance of conclusions that those conclusions very often overwhelmed human evidence to the contrary.

Soon animal experimenters were asking for and receiving money for their research. Animal breeders began to profit. Suppliers of lab equipment enjoyed their expanding market. And so forth. The growing new industry seemed useful for the study of diseases, even though there were huge disparities in results between animal species, and between animals and humans. Then, in the 1930s a single incidence of a drug effecting an animal the same as a human effectively routinized the use of animals for drug development too. Of course, the same problems persisted: Animals often reacted differently to the same chemical substances.

However, the pharmaceutical industry was off and running, developing strong ties with animal experimenters and using their results to boost profits. The disaster of thalidomide, a drug designed to suppress morning sickness that led to over 10,000 babies with birth defects, spurred the US Congress to offer the American public every possible guarantee of medication safety. That "guarantee" took the form of animal testing.

Nevermind that thalidomide itself had been tested on animals prior to release and had not imposed birth defects on them. And that even after scientists knew what to look for, they found birth defects from thalidomide only occasionally.

In approximately 10 strains of rats, 15 strains of mice, 11 breeds of rabbits, 2 breeds of dogs, 3 strains of hamsters, 8 species of primates and in other such varied species as cats, armadillos, guinea pigs, swine and ferrets in which thalidomide has been tested, teratogenic effects have been induced only occasionally.

Nevermind also that there was already ample evidence that chemicals react very differently in different species. By legislating that all drugs must prove safe and effective in animals prior to release, the government created a legal safehouse for pharmaceutical companies and any other industry with a product of questionable medical safety. Ever since, when lawsuits occur, big business can justifiably claim that they acted with due diligence to the full extent of the law. Inevitably, big business' enthusiasm over this legal safety net has played a large role in making animal experimentation a sacred cow.