ANIMAL TOXINES. 
§ 677-] 
5i7 
so as to separate as much as possible the inorganic constituents. The 
alcoholic extract is evaporated, dissolved in a little water, neutralised 
with soda, acidulated with nitric acid, and precipitated with phospho- 
molybdic acid. The phospho-molybdic acid precipitate is decomposed 
with neutral lead acetate, which process may be facilitated by heating on 
the water-bath. After getting lid of the lead by treatment with SH 2 , 
the fluid is evaporated to a syrup and alcohol added, by which process 
many basic toxines may be eliminated as hydrochlorides ; or they can 
be converted into double salts (of platinum or gold) for the purpose of 
separation. In the filtrate from phospho-molybdate, bases may also be 
found by treating with lead acetate to get rid of the phospho-molybdic 
acid, and then adding certain reactives. Since it is but seldom that the 
hydrochlorides are obtained in a state of purity, it is preferable to convert 
the substance separated into a gold or platinum salt or a picrate, since the 
greater or less solubility of these compounds facilitates the purification of 
individual members ; but which reagent is best to add, must be learned 
from experience. The melting-point of these salts must always be taken, 
so that an idea of their purity may be obtained. It is also to be noted 
that many gold salts decompose on warming the aqueous solution ; 
this may be avoided by the addition of hydrochloric acid. The hydro¬ 
chlorides of these bases are obtained by decomposing the mercury, gold, 
or platinum combinations by the aid of SH 2 , while the picrates can be 
treated with hydrochloric acid and shaken up with ether, which latter 
solvent dissolves the picric acid. 
Considerable difficulty in the purification of the bases is caused by 
a nitrogenous, amorphous, non-poisonous, albumin-like substance, which 
passes into all solutions, and can only be got rid of by careful pre¬ 
cipitation with an alcoholic solution of lead acetate, in which it is 
soluble in excess. This albuminoid forms an amorphous compound with 
platinum, and acts as a strongly reducing agent (the platinum compound 
contains 29 per cent, platinum). When this albuminoid is eliminated, 
then the hydrochlorides or the double salts of the bases crystallise. 
§ 677. The Benzoyl Chloride Method. —The fatty diamines in dilute 
aqueous solutions, shaken with benzoyl chloride and soda, are converted 
into insoluble dibenzoyl derivatives ; these may be separated from 
benzamide and other nitrogenous products by dissolving the precipitate 
in alcohol, and pouring the solution into a large quantity of water. 1 
Compounds which contain two amido groups combined with one 
and the same carbon atom, do not yield benzoyl derivatives when 
shaken with benzoyl chloride and soda. Hence this reaction can be 
utilised for certain substances only. The solution must be dilute, 
because concentrated solutions of creatine, creatinine, and similar 
bodies also give precipitates with benzoyl chloride ; no separation, 
1 L. V. Udransky and Baumann, Ber., xxi. 2744. 
