Fig. 1.

¹³C kinetics after administration of the ¹³C tracer to the same dog during resting conditions in period 1 (–▲–) and period 2 (–●–). Concentrations of carbon dioxide in the analysed breath bag during resting conditions in the same dog in period 1 (--△--) and period 2 (--○--). ppm, Parts per million.