5b. With halogens, phosphorus pentachloride and phenylarsenious chloride, products are obtained which would be expected, providing the original substances were mechanical mixtures of aldehyde and arsine. The compounds may be titrated quantitatively with a solution of iodine in ether. 5c. The compounds form unstable addition products with halogen acids, and stable addition compounds with chloroplatinic acid. 6a. The tetrahydro-dioxdiarsines formed according to Equation (l b) , oxidize in the air to give aryl arsine oxides and aldehydes. This is particularly noticeable where the product is a derivative of formaldehyde. 6b. The compounds form douhle salts with chloroplatinic acid and cupric chloride. Bc. With iodine or phosphorus pentachloridc, products are obtained which might be expected from a mixture of aryl arsine and aldehyde. 7. Aromatic primary arsines reduce aromatic aldehydes to alcohols with the formation of arsenobenzene, when a mixture is made at room temperature with no hydrochloric acid as a catalyst, or when a mixture is heated with or without hydrochloric acid. 8. A discussion of the structure of the various condensation products is given. 9. The probable mechanism for the condensation of aromatic primary arsines and aromatic arsine oxides, antimony tri-chloride, ctc., is discussed. URBANA, ILLINOIS