66 Causes and Course of Organic Evolution 



methods for artificial synthesis of well knoT\Ti organic com- 

 pounds. 



Thus Benzoic aldehyde (CtHqO) is formed in plant tissues 

 such as seeds of bitter almond, when the glucoside amygdalin 

 is spht up by the ferment emulsin or synaptase. Fisher (Ji.0: 59) 

 gives its artificial preparation as follows: Benzyl chloride and 

 copper nitrate are boiled in water for five to eight hours. The 

 resulting oil is extracted with ether, the ether is evaporated, 

 and the oil, shaken with sodium bisulphite, yields crystals of 

 aldehyde-bisulphite. The crystals are warmed with dilute 

 sulphuric acid, and the aldehyde, now set free, is extracted 

 with ether. 



Quinoline or quinoleine (C9H7N) is obtained from alkaloids 

 of the quinine (Rubiacese) and strychnine (Loganiacese) fam- 

 ilies. Skraup has synthesized it thus: Nitrobenzene, aniline, 

 glycerine, and concentrated sulphuric acid are cautiously mixed 

 in a flask, and heated till reaction starts. The mixture is 

 then boiled for two hours, diluted with water, the nitrobenzene 

 is distilled off, arid an alkaline remainder is distilled with steam, 

 when quinoline appears. 



Grape-sugar (CeHigOg), a crystalline carbohydrate of wide 

 occurrence in plants, has been obtained by Soxhlet through 

 mixing hydrochloric acid and alcohol; this when warmed has 

 cane-sugar added to it, and the whole is kept hot till the sugar 

 is dissolved. When cold a small quantity of grape-sugar is 

 added, and the mixture, frequently stirred, should stand for 

 several days at room temperature, when the grape-sugar crystal- 

 lizes out as small colorless crystals. 



Dulcite (C6Hi406), another and related carbohydrate to the 

 last, occurs in such families as the Celastracese and Scrophu- 

 lariacese. It is obtained by dissolving the allied carbohydrate 

 galactose in ten times its volume of water, and adding sodium 

 amalgam, the mixture meanwhile being neutralized by dilute 

 sulphuric acid. The solution, separated from the mercury 

 of the amalgam, is poured into hot 95 per cent, alcohol, and 

 on concentration over a water bath the dulcite separates as 

 crystals. 



In contrast to the above, relatively large quantities of each 

 can be produced in plant cells that show no marked indication 

 of chemical reactions proceeding; that do not evolve extra 

 amounts of heat, even when, as in large flower clusters that 

 are actively metabolizing, a few degrees of rise in temperature 



