88 



by alcohol, but more completely by acetone. The alcoholic extract is 

 acid to litmus. 



In this alcoholic extract the presence of an indicator was observed. 

 When the extract is somewhat concentrated, the colouf becomes a beau- 

 tiful pink which is destroyed by sodium hydrate, added to saturation 

 and concentiating the solution to dryness. The colour is not restored 

 by hydrochloric acid. (This colour substance needs further study.) 



Ether extract (9*97 per cent.) is nearly colourless, yielding upon 

 evaporation a residue resembling white beeswax This residue is 

 quite soluble in chloroform, but only partially soluble in benzine or 

 alcohol (Soluble in hot alcohol.) The aqueous washings of this 

 extract give an acid reaction with litmus and a precipitate with lead 

 acetate. 



Chloroform extract (11 20 per cent.) is colourless and slightly turbid. 

 The residue upon evaporation, is wax-like, and hard (much resembling 

 the residu ■ from the ether extract.) Thi.'? residue is pir ially solub e 

 ill ether, and almost insoluble in alcohol and benzine. The aqueous 

 washings from this extract give an acid reaction to litmus 



Aceto- e ex ract (5*98 per cent ) is of a yellowish colour. The evapo- 

 ration residue has a pungent, slightly aromatic odour and a dark brown 

 colour resembling the extract of plants. The residue is almost wholly 

 soluble in alcohol, chloroform and amylic alcohol ; bnt slightly soluble 

 in ether, and insoluble in benzine. '^ 



As the substances removed from the latex by volatile solvents were 

 in the nature of material foreign to the enzyme, no systematic exam- 

 ination was made. These solvents do not seem to remove any proteid 

 compounds save in the case of benzine, which extract gave a faint 

 proteid reaction. 



As a result of a hasty examination of these extractions we may as- 

 sume that they contain colouring matter ; "vegetable extractive mat- 

 ter ;" hard and soft waxes ; hard and soft resins ; a volatile resin; a 

 substance of the nature of fatty acids ; pectose compounds. ^ * 



WATER SOLUBLE CONTENTS. 



The dried latex extracted by repeated washings with water gives 

 82'74 percent, of matter soluble to a clear greenish- yellow solution. 

 The watery extract is of acid reaction and responds to the usual tests 

 for the presenceof proteids, such as Millon's reagent ; the xanthoproteic 

 and bitter tests, etc ; precipitates are formed by alcoholic tannin, 

 picric acid, platinum chloride, metaphosphoric acid, lead acetate, 

 Mayer's reagent, mercury bichloride, potassium ferrocyanid and acetic 

 acid. The presence of several forms of proteid substances is also 

 shown by the following : 



The filtered solution (noted above) is rendered turbid by heating to 

 the boiling point. Upon continued boiling a very fine precipitate is 



(13) The alcoholic and acetone extracts give slight indications of the presence 

 of nitrogenous matter by the soda-lime process. 



(14) Malic acid has been noted as being present in the latex of the papaw. The 

 acid principles of these extracts of the milk when subjected to the usual tests for 

 malic acid, gave but slight indications of its presence. 



The aqueous solution of the latex was examined at length and judging by the 

 reactions noted in the text-books, and compared with malic acid itself, the con- 

 clusion was reached that no malic acid or malates were present. 



