152 PLANT PRODUCTS 



but is very readily soluble in small traces of acid, in the 

 absence of other salts. From such a solution the edestin is 

 readily precipitated by sodium chloride. Edestin, in fact, 

 has proved to be a fairly strong base, and the combined acid 

 in its salts can be titrated by potash and phenol-phthalein. 



The maximum acid binding power of edestin is very 

 high indeed. The solubility of edestin in salt solutions is 

 approximately the same, but the iodides and bromides dis- 

 solve edestin more readily than the chlorides. Acetates 

 behave in a somewhat remarkable manner, for the acetates 

 of the alkalies have no solvent action on edestin, while the 

 acetates of heavy metals dissolve it freely. The acetates 

 of lead, copper, and silver, which are commonly supposed 

 to be protein precipitants, are as good solvents for edestin 

 as is pure acetic acid, provided other salts be absent. The 

 metallic ion of the acetate unites in organic combination 

 with the protein. Corylin, from hazel nuts, is characterized 

 by containing the very high amount of 19 per cent, of nitrogen, 

 of which nearly one-third is basic nitrogen. The proteins 

 in this group are, on the whole, characterized by high 

 percentages of nitrogen, with moderate amounts of ammonia, 

 and very high amounts of basic nitrogen, with large quantities 

 of arginine and moderate amounts of histidine. The castor 

 bean contains toxic substances, which appear to be of 

 protein character, although this is not accepted by all 

 workers, but preparations have been made of ricin, of which 

 2o\)o P^^"^ o^ ^ milligram per kilogram weight was a fatal 

 dose when subcutaneously injected into rabbits, and such 

 rich preparations contain a high percentage of albumen. 



The Alkaloids. — Opium is the dried milky juice (latex) 

 of the unripe capsules of the poppy. The opium poppy is 

 cultivated in India and China from seed, which is sown from 

 November to March, and the crops are ready from May to 

 July. A few days after the petals have fallen the capsules 

 are cut round the middle with a knife, and on the following 

 morning the juice has flowed out, hardened, and is ready for 

 collection. After further drying on poppy leaves, the dark 

 masses are made up into lumps. Opium is used medicinally, 



