1. The effects of cocaine and its decomposition products were studied on the growth of the young roots of Lupinus albus.
2. The results obtained were compared with similar experiments on animal tissues.
3. It was found that, while cocaine is the most toxic of these compounds studied for animal tissues, it was of comparatively low toxicity in respect to its effect on the growth of roots. On the other hand, sodium benzoate, being practically non-toxic for animals, was the most toxic of the compounds studied for the plant roots.