The Analysis of Direct Inhumanity

The incidence, character and severity of direct inhumanity
should be seen as separate, but indivisible,
parts of the same whole concept.


In the first Wisdom of Russell and Burch comment in PiLAS,1 their concept of inhumanity, its sources, diminution or removal were discussed. In the outstanding Chapter 4 of The Principles of Humane Experimental Technique,2 they distinguished between direct inhumanity, “the infliction of distress as an unavoidable consequence of the procedure employed”, and contingent inhumanity, “the infliction of distress as an incidental and inadvertent by-product of the use of the procedure, which is not necessary for its success”.

They saw the avoidance of contingent inhumanity as mainly a matter of good husbandry, diligent care and common sense, but correctly saw the diminishing or removal of direct inhumanity, defined as unavoidable, as a completely different matter.

They outlined “three obvious ways of classifying procedures in terms of their direct inhumanity”,
namely, “incidence (e.g. in control and experimental groups), severity (e.g. the severity of a procedure in those animals that are affected), and special character (e.g. post-operative pain and distress, effects of particular pathogens, or death due to various types of toxic chemical)”, as follows:

“The incidence of direct inhumanity is a convenient concept in connection with assay, toxicity testing, or diagnosis. A procedure may be such that it causes no (or negligible) distress to some or most of the animals used, while likely or even certain to cause distress in a certain (often unpredictable) proportion, as a necessary consequence of the nature and object of the procedure. Incidence is an important factor to be considered in weighing the inhumanity of a procedure as a whole. Often, incidence is total — that is, all animals treated are likely and expected to react similarly and specifically to the treatment. A special case of incidence is the distinction between experimental and control groups in many types of experiments. Sometimes the experimental group is more likely to suffer (as in the study of the effects of particular operations), sometimes the controls (as in chemotherapy or immunisation experiments, where the unassisted group is expected to succumb).”

“The special character of procedures is often a unifying factor among experiments of extremely diverse objects. We might distinguish here such effects as general postoperative pain and stress, specific effects of widespread operations (such as adrenalectomy), modes of death due to various groups of poisons, general and specific effects of groups of pathogens, etc. We might note a special sort of semicontingent inhumanity — a component of a procedure which is irrelevant or harmful to its success, but more or less indispensable to its performance. For instance, pyrogen tests often involve nothing more serious than a rise in temperature which would not even send most humans to bed. But, for their performance, animals are often restrained for periods of over an hour, and this may impose some distress.”

“This analysis might form a starting point for the third dimension of classification — the severity of a procedure in those animals which are affected.”

The problem of severity was addressed in detail in Chapter 2 of The Principles, and is such a huge issue that it deserves to be considered separately in a future issue of PiLAS.
Russell and Burch went on to say that incidence, character, and severity are at least partly independent
variables, and that “a cross-classification will ultimately be required along all three dimensions”. I think that what they mean by this, is that we should see them as separate, but indivisible, parts of the same whole concept.

Significantly, they then turned to a “consideration of the ways in which [direct] inhumanity can be and
is being diminished or removed”. These ways, they said, “can be discussed under the three broad headings
of Replacement, Reduction, and Refinement, [which] have conveniently been referred to as the Three Rs of humane technique”. Convenient in 1959, maybe, but now essential — for ethical, scientific and legal reasons — that the individual Rs are also seen as separate, but indivisible, parts of the same whole. For example:
— Replacement can be partial, rather than total, contributing to a Reduction in the number of animals
needed for a particular purpose, and/or to Refinement (by, for example, screening out the most toxic chemicals, so that extreme severity is unlikely in animals used to test those chemicals at lower doses);
— a step-wise procedure can be used as a Refinement, obviating the need to test at certain doses, thus leading to a Reduction in the overall number of animals required;
— Refinement can also be used to make it clear where Replacement is needed and/or is possible;
and finally
— recognising the limitations in the use of animal models for certain purposes, can result in
Reduction, leading to Replacement. Replacement will occur when the need for more directly-relevant human alternatives is necessary, and intellectual energy and other resources are released to encourage them to be made available and implemented.


1 Anon. (2012). The Wisdom of Russell and Burch. 1. The concept, sources and incidence of inhumanity and its diminution or removal through implementation of the Three Rs. ATLA 40, P15–P16.
2Russell, W.M.S. & Burch, R.L. (1959). The Principles of Humane Experimental Technique, xiv + 238pp. London, UK: Methuen.

The Principles of Humane Experimental Technique is now out of print, but the full text can be found at An abridged version, The Three Rs and the Humanity Criterion, by Michael Balls (2009), can be obtained from FRAME.

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