Vivisection: a methodological error

Starting from the first laws of mechanics and thermodynamics, the same method has been used to explain all sorts of natural  phenomena, including complex biological ones: the method was  trying to break down and reduce these complex phenomena into  separate and simpler mechanical elements. This approach led to  the taking hold of mechanism and reductionism which, from being  a method used to learn the simplified aspects of complicated  processes, it was soon turned into an ideology that equated living  organisms to machines produced in series. This leads nowadays  to a reversal in the logic of things: in order to study things,  instead of methodologically simplifying them, partial knowledge  is applied to reality, thus simplifying it. It is thus that plants  and animals are treated like machines and natural productive  cycles are overturned to the point of becoming linear processes  just like industrial ones. Also human beings can be equated to  machines and therefore, by studying and vivisecting the animal-machine,  people think it is possible to understand the functioning of  the man-machine: it is no wonder then that present-day medicine  expects to cure Man by simply replacing parts when they have  stopped working and that health care services favour treatment  over disease prevention; while diseases, among other things,  increasingly stem from the mechanical transformation, or rather  the simplification, of the reality in which we live.

Said logic rests upon false premises: any biologist knows that  different animals can present anatomical and physiological characteristics  that are similar or equal but also many others that are entirely  different. This consideration alone is sufficient to make the  animal model entirely unreliable because any animal species can  only be a self-referencing model. Moreover, the animal-machine  model has also lost sight of the inter-relations between the  environment and organisms and between the different parts of  the same organism, thus ignoring the fact that individuals are  self-enclosing entities. In fact, the animals used for experimentation  are artificially selected and kept in cages away from the stimuli  they need to develop their own defense mechanisms. This means  that a laboratory animal is nothing like its cogene living in  the wild and any experiment performed on it cannot even be extrapolated  to other animals that belong to its own species but that live  in a normal space-time context.

 In this respect, N.D. Barnard and S.R. Kaufman wrote (on Scientific American, February 1997): "Animal 'models' are, in the  best of cases, a good imitation of human conditions but no theory  can either be approved or rejected on the basis of an analogy.  Nevertheless, in discussing the validity of contrasting theories  in medicine or biology, studies conducted on animals are taken  as proof. In such a context, animal experimentation primarily  serves as a rhetoric pretext. And, by using different types of  animals in different protocols, experimenters can find evidence  to prove any theory whatsoever. For example, animal testing has  been used as proof both in favour and against the carcinogenic  potential of smoking."

In order to corroborate the above statements, we could mention  a long list of errors and mismatches between different animals,  starting with the dosage of compounds that turn out to be lethal  on similar animals. In this respect, mention must first be made  of a drug of natural origin that is no longer in use, namely  strychnine, which is an alkaloid that enhances the excitability  of sensory and motor neurons. In actual fact, in human use, it  is more known for its toxic (it is actually a poison) than its  therapeutic effect. The lethal oral dose for a number of animals  is the following (from R. Kirk: "Current Veterinary Therapy"):  cattle  0.5 mg/kg (of body weight); horses  0.5 mg/kg; dogs  0.75 mg/kg; cats  2.0 mg/kg; rats  3.0 mg/kg;  chicken  5.0 mg/kg.

What relationship is there between the above dosages and what  is the dose that can consequently be extrapolated for Man? It  is impossible to make a prediction: in fact, if reference is  made to the dose for pigs (often considered to be the closest  model for Man), one would realize that it corresponds exactly  to the dose of strychnine used in human medicine.

Still sticking to alkaloids, scopolamine, an anticholinergic  drug, is lethal for Man at an oral dose of 5 mg while the bodyweight-correlated  dose needed to kill a dog or a cat is almost 360 times greater.  It is therefore clear that the lethal dose of a given substance  is not conducive to predict the lethal dosage for any other animal, including Man.

Another way of explaining this is based on the consideration  that even very similar animal species possess small genetic differences  that lead to the production of enzymes, which are the essential  proteins that enable the distinctive chemical reactions involved  in an organism's metabolism, that are nonetheless sufficient  to modify the chemical-physical conditions in which these enzymes  come into play. Moreover the metabolic processes differ widely  between species, including their detoxication potential, meaning  thereby the way they eliminate a toxic substance, drugs included,  after having modified it. In addition, animal carcinogenicity  testing, besides being ambiguous, is also costly and time-consuming.  The scarce reliability of extrapolating data relative to animals  to Man is well known throughout the scientific world; I shall  only mention a few examples taken from the work of famous authors:

1. "Laboratory-induced cancer has nothing to do with naturally occurring cancer in Man" (Prof. Sabin in a presentation  made in Naples in June 1978);

2. "Tumours in mice, rats, chicken and guinea pigs are essentially different from those occurring in Man, having a different way  of forming, a different way of growing and a different way of metastasizing" (Prof. U. Veronesi in his book entitled "An  Incurable Disease");

3. "Great caution is required in applying to Man conclusions  that arise from the study of mutagens and carcinogens in laboratory  organisms. As a matter of fact, studies on different biological  experimental systems sometimes provide different outcomes; this  ensues not only from observing organisms that are very distinct  but also those that are similar" ("Treatise on Genetics",  UTET, 1991, by Curtoni, Dallapiccola, De Marchi, Mateinz, Momigliano  Richiardi, Piazza).

This makes it practically impossible to run such tests on the  tens of thousands of new chemical compounds discovered each year  and which add on to the list of other millions of chemical substances  that are already known to be potentially carcinogenic.

All this, as I have already stated, is a well-known fact among researchers who often use the distinctive characteristics found  in laboratory animals in order to obtain pre-established results.

Because of these errors, all experimental data obtained from  animals give us no additional knowledge: the same outcome might  also occur in Man but it also might not. The only way of knowing  whether there exists a correspondence between Man and laboratory  animals is by experimenting the very same substances on Man.

Animal experimentation therefore is not only useless and ambiguous but also gives industries an alibi for marketing substances whose carcinogenic potential can ultimately only be tested on Man.

Gianni Tamino

Professor of Biology at the University of Padoa and President  of EQUIVITA Scientific Committee