bility. It is to be noted first that as a
result of the treatment with the diluted acetone and further dilution
after the specific action is completed, collecting the disintegrated
product on a filter and washing with water, the loss of weight sustained
amounts to 3 to 4 p.ct. This loss is due, therefore, to products
remaining dissolved in the filtrate--that is to say, in the much diluted
acetone. These filtrates are in fact opalescent from the presence of a
portion of nitrate in a colloidal (hydrated) form. On distilling off the
acetone, a precipitation is determined. The precipitates are nitrates of
variable composition, analysis showing from 9 to 12 p.ct. of nitric
nitrogen. The filtrate from these precipitates containing only
fractional residues of acetone still shows opalescence. On
long-continued boiling a further precipitation is determined, the
filtrates from which are clear. It was in this final clear filtrate that
the product assumed to cause the instability of the original nitrate
would be present. The quantity, however, is relatively so small that we
have only been able to obtain and examine it as residue from evaporation
to dryness. An exhaustive qualitative examination established a number
of negative characteristics, with the conclusion that the products were
not direct derivatives of carbohydrates nor aromatic compounds. On the
other hand the following positive points resulted. Although the original
diluted acetone extract was neutral to test papers, yet the residue was
acid in character. It contained combined nitric groups, fused below 200 deg.
giving off acid vapours, and afterwards burning with a smoky flame. On
adding lead acetate to the original clear solution, a well-marked
precipitation was determined. The lead compounds thus isolated are
characteristic. They have been obtained in various ways and analysed.
The composition varies with the character of the solution in which the
lead compound is formed. Thus in the opalescent or milky solutions in
which a proportion of cellulose nitrate is held in solution or
semi-solution by the acetone still present, the lead acetate causes a
dense coagulation. The precipitates dried and analysed showed 16-20
p.ct. PbO and 11-9 p.ct. N. It is clear that the cellulose nitrates are
associated in these precipitates with the lead salts of the acid
compounds in question. When the latter are obtained from clear
solutions, i.e. in absence of cellulose nitrates, they contai