Comparative Study of Chlorophyll. 417 



The boiling, which must be gentle, lasts for half to three- 

 quarters of an hour. 



2. Wash till the water runs off quite colourless. 



3. Dry the material at a low temperature as quickly as 

 possible. "When dry, the material may be used at once, or 

 kept for future investigations in the dark, 



4. Treat the dried material with absolute alcohol, and a 

 dark green solution is got. After a time no more colouring- 

 matter is taken up, and after the first quantity of alcohol 

 is poured off, the material is extracted with a second, and 

 it may be third quantity of alcohol, till most of the colour- 

 ing-matter has been removed. 



All these manipulations, as also the succeeding ones, have 

 to be done in a darkened room, since the colouring-matter 

 is very susceptible to light. 



5. Evaporate the alcoholic extract to one-eighth of its 

 volume. 



6. Saponify by Kiihne's method — 



(«.) Make a solution of caustic soda by taking 1 

 part of NaOH, 5 parts of water. 



(&.) Add of this solution 40 to 50 c.cm. to 2i litres of 

 the concentrated alcoholic solution thus : "While 

 the alcoholic extract is boiling, add the caustic 

 soda solution drop by drop, stirring all the time. 



(c.) Drive off the alcohol and add water; evaporate 

 the water to a small quantity. Then add 

 alcohol for a second time, and the saponification 

 is completed. 



7. To get the soap in a solid form, evaporate the alcohol, 

 add water and an excess of sodium chloride. Thus we get 

 the soap separated in the form of black-green granules. 



8. Add petrol-ether to the soap, and a dark yellow colour 

 is extracted. [If I understand the author correctly, it is 

 more advisable to treat the black -green granules (7) first 

 with ether (9), and then with petrol ether (8), as less of the 

 latter will thus be required for the removal of the yellow 

 colouring matter. — G. M.] 



9. Next, wash the soap with ether, which will remove 

 foreign bodies, along with a small quantity of colouring-matter. 



10. Treat the soap with ether, mixed with a few cubic 

 centimetres of alcohol, and a clear green extract results. 



TRANS. BOT. SOC. VOL. XVIII. 2 S 



