87 



species. This h true not only of the Carica Papaya, in universal 

 cultivation by the natives, bu also in other species the fresh juice 

 will blister and cauterize almost instantly. A caustic property is not 

 unusual in many tropical plants. In the railk of the papaw it is not 

 due to acid constituents, as it is still present if the slighf. aci lity is 

 neutralized It can be removed by chloroform and ether, and is either 

 removed or destroyed in some of the processes of separating the fer- 

 ments (precipitation). 



The corrosive constituent is not volatile and remains in the dried 

 juice. An examination of many of the preparations sold in our market 

 under the name of " papain," etc., shows that this corrosive property 

 had not been altogether removed. 



ANALYSIS OF PAPAW LATEX. ^ ^ 



This latex is an emulsion of fats and wax, containing also extractive 

 matters, albumen and salts, as shown by the following: 



Alcoholic extract (7-16 per cent.) is coloured, astringent and has a 

 somewhat acrid taste. The concentrated extract is dark brown, 

 resembling well known solid extracts. Evaporated residue is only 

 slightly soluble in ether and chloroform, but is partially so in a cold 5 

 per cent, solution of sodium hydrate. It is further dissolved upon 

 heating. Alcohol added to this sodium hydrate mixture dissolves it 

 completely Acid added to the aqueous or ale hoi alkaline mixture 

 gives a saponification indicating resins. 



Some "bservers have reported a glucosidal body in the Carica 

 latex. The usual tests for such substances, when applied to this 

 extract, give negative results. In my hands this extract gave no in- 

 dicati 'U of tannin, although this substance has been reported as present 

 in the milk. The acrid resins of the papaw are more or less extracted 



(12) Owing to the length of this paper, the detailed methods of analysis have 

 been omitted. In most cases the methods were those in common use. 



