I 164 e. H. STONE A S D F , If. EATOS. arsenite.' This higher percentage of the fatty acid, however, s h o w that butyric acid has a stronger tendency to replace arsenious acid in the zinc as well as in the copper compounds. In conclusion, I would express my obligations to F. 0. Woodruff for his carefully prepared bibliography which he placed at my disposal and to R. Corr and Fred Upson, of this laboratory without whose careful work in preparing and analyzing compounds, only a small part of which are given here, this work could not hare been brought to completion.