On the reaction between metaphosphoric acid and egg albumin.

METAPHOSPHORIC acid is considered to be a protein-precipitating reagent. Pohl [1889], Lorenz [1890], and Fuld [1902] analysed precipitates obtained from proteins with metaphosphoric acid. Their results did not lead to any important interpretation because at that time the knowledge of protein chemistry was not yet sufficiently developed. In 1935 Schofield gave theoretical reasons for assuming a chemical combination between metaphosphoric acid and the positively charged amino-groups of the protein molecules. Since no experimental work on the question has been published hitherto, we decided to attack this problem with improved analytical methods. We were well aware of the difficulty that solutions of metaphosphoric acid contain various association-products and certain amounts of sodium metaphosphate and orthophosphoric acid which might complicate the reaction to be studied. During our investigations we did not, however, observe any indication that other forms of metaphosphoric acid than the simple P03ion take part in the reaction. The same opinion has already been expressed by Pascal [1924] on the basis of his studies of the inorganic reactions of metaphosphoric acid. Experimental