Genetical and Cytological Proof of Non-disjunction of the Fourth Chromosome of Drosophila Melanogaster

droxide, and the lysine as picrate.The residual solution contained an' amount of non-amino nitrogen corresponding approximately to that- determined by Van Slyke's method in excess of the arginine and histidine non-amino nitrogen.Attempts to crystallize the free base or its derivatives have been success- ful only with the phosphotungstate.Recrystallization of the phosphotungstate yields a product in which the ratio, Total N: Amino N = 2 : 1.The free base -prepd.from the recrystallized phosphotungstate is hy- groscopic, and decomposes slowly when dried at 1000.It does not appear to be a peptide, for the ratio of amino to total nitrogen is not increased by boiling 40 hours with 20 per cent hydrochloric acid, nor by heating 8 hpurs in a bomb tube at 1250 with 25 per cent sulfuric acid.We are engaged in the preparation of larger.amounts of the substance in the hope of determining its structure.