§ Mr. Boyesasked the Secretary of State for the Home Department what proportion of LD50 tests on animals are carried out without anaesthesia at any stage in Government research laboratories, in university laboratories and in all laboratories; and if he will make a statement.
§ Mr. MellorThis information is not available. LD50 tests, however, are not normally performed under anaesthesia unless an anaesthetic agent is itself the subject of the test. The number of such cases is likely to be small. The purpose of an LD50 test is to determine the toxicity of a particular substance and the administration of an anaesthetic — which is itself toxic — would probably invalidate the result. Even if anaesthetics were compatible with the test, it would be difficult to calculate an appropriate dose because of the unpredictable duration of the test.
19WThe Government welcome and encourage the replacement of LD50 tests by other forms of acute toxicity test wherever possible. In the limited circumstances where it is still necessary to perform LD50 tests, they are carried out under the terms of the Cruelty to Animals Act 1876. The pain condition under the Act requires any animal in severe and enduring pain to be immediately and painlessly killed.