We will, if asked, disclose the contents of responses to this letter and the identities of respondents. Please let us know if you would prefer us not to do either or both of these things in your case. The use of animals in medical research - an example 1. Whatever one thinks of the ethics and validity of animal experiments it is clear that some aspects of animals are at least similar to man. For instance the heart of all mammals is a pump that contains four chambers and the exit from each chamber has a valve.
Blood is brought into the heart by veins and carried away by arteries.
The hearts of other orders of animal are distinct. For example those of crabs only have one chamber. Therefore it appears more useful to use the heart of any mammal to model the heart of a human being as a pump than that of a crab. Some elements of particular mammals are more specialised than the same elements in man. For example the ears of rabbits are extremely efficient organs for temperature control whereas in man the ears do not have that function.