Controversy
Many people are morally opposed to the use of animal vivisections when applied to human medicine on the basis that an animal's body is an inaccurate model for the human and may therefore lead to incorrect anticipations of the effect drugs and surgical procedures may have when applied to a human patient. In addition animal rights and animal welfare campaigners have ethical objections concerning the harm done to the animals. Others claim that the benefits to medicine and science from vivisection are substantial, and outweigh the harm caused to animals. It should be noted that not all vivisection is intended to result in medical treatments for humans. Other purposes of vivisection include: developing veterinary treatments, testing the safety of newly developed products such as cosmetics and cleaning products, and satisfying scientific curiosity.
Often medical discoveries have been made without animal experimentation and then the tests on animals have followed afterward. In these cases, such as the initial discoveries of vaccination and anaesthesia, the belated animal experiments cannot legitimately be credited has having played a valid role. But do such experiments ever help lead to a medical advance? A significant number of people believe so, though balanced by a large number of the opposite opinion. In support of animal experimentation, all mammals have the same basic organs. Still, there are undeniable differences between human and non-human animals. About a third of medicines used by veterinarians are also used in humans. The severity of these differences are evaluated on an experiment-by-experiment basis.
Some practitioners claim that operating on a live animal produces more useful information than if the test subject were euthanized first. This is especially the case in fields such as neurobiology, where post-mortem activity is either nonexistent or very different. Directly observing how organss and other bodily systems respond to experiments is not possible during necropsies but the advantages of such direct observation is questioned by some. Tissue cultures, organ cultures and computer simulations are in certain cases taking the place of the older, controversial methods. In America, Johns Hopkins University is leading the way in the development of these new methods and in Britain the charity group F.O.R.C.E (based at the Royal Devon and Exeter Hospital) and The Doctor Hadwen Trust (based in London, England).
A few scientists have attempted to drive a wedge between research and ethics, claiming that science shouldn't be concerned with unscientific matters like moral right or wrong. Nazi doctor Josef Mengele and the Japanese Unit 731 both ordered human vivisections on concentration camp prisoners. There have been other cases of Human experimentation, which have been condemned by the vast majority of the scientific community.
Intellectuals have written many books tackling the rights and wrongs of experimentation on animals. Anti-vivisectionist Christian author C.S. Lewis strongly expressed his views in his book, The Problem of Pain. He wrote on moral and theological grounds.
British physiologist Marshall Hall (1790-1857) was an animal experimenter who, in 1831, proposed five principles to govern animal experimentation:
- An experiment should never be performed if the necessary information could be obtained by observations
- No experiment should be performed without a clearly defined and obtainable, objective
- Scientists should be well-informed about the work of their predecessors and peers in order to avoid unnecessary repetition of an experiment
- Justifiable experiments should be carried out with the least possible infliction of suffering (often through the use of lower, less sentient animals)
- Every experiment should be performed under circumstances that would provide the clearest possible results, thereby diminishing the need for repetition of experiments
The first law regulating animal experimentation was the 
