  We report experiments on the generation of third and fifth harmonics of
millijoule-level, tightly focused, femtosecond laser pulses at 2.2 {\mu}m
wavelength in air. The measured ratio of yields of the third and fifth
harmonics in our setup is about 2 \cdot 10-4. This result contradicts the
recent suggestion that the Kerr effect in air saturates and changes sign in
ultra-intense optical fields.
