Uncontrollable atmospheric conditions which can affect animal experimentation.

: In our programs of investigation into mechanisms of molecular action of toxic substances, we have had occasion to observe the appearance of anomalous values in biochemical parameters, which we put down to cyclic rhythms or coincidences with the following phenomena: meteorological (storms), geological (earthquakes), and astronomical or phenological (eclipse and lunar phases). This work reviews such observations, which suggest that besides the environmental conditions of the animal room (illumination, humidity, temperature, noise) it is necessary to consider all the external circumstances which occur at the moment of the experiment.