300 On Carrageen. Chondrus crispus 



It may be remarked that the accurate determination of hygroscopic 

 moisture is a matter of some little difficulty owing to the fact that the 

 material when dried to constant weight in a steam oven may show 

 signs of darkening and decomposition at or about the final stage. 



Ash Content. 



Carrageen contains a relatively high percentage of ash both in the 

 plant and in the scale; in the latter instance the amount varies according 

 to the method of preparation, the earlier fractions of cold water extracts 

 yielding the greatest amounts. The following are typical analyses: 



A. The untreated plant gave 14-6 per cent. ash. 



B. Scale carrageen: 



/ 5th fraction gave 27-07 per cent. ash. 



(i) Cold water extract ... ... ... / 10th fraction gave 24-32 per cent. ash. 



' 30th fraction gave 21-50 per cent. ash. 



(ii) Hot water extract of residue remaining \ 



after more or less complete extraction V gave 16-30 per cent. ash. 



with cold water J 



(iii) Hot water extract. (Plant extracted / no _„ , , 



x '.,,,, , , > v gave 22- /0 per cent. ash. 



with hot water only) \ 6 r 



(iv) Residue from (iii) ... ... ... gave 5-19 per cent. ash. 



Church gives 14-15 per cent, of ash in the dry plant, Fliickiger and 

 Hanbury 1 found that the aqueous extract of the plant and the plant 

 itself contained more than 15 per cent., Czapek 2 gives 20-6 per cent., 

 Fliickiger and Obermaier 3 found 16 per cent., whilst Jolles found but 

 1-59 percent. This last result is obviously incorrect, but the mistake may 

 be due to a displacement of the decimal point. 



It was found impossible to remove the mineral constituents by 

 dialysis, a fact commented on by previous authors; indeed in one in- 

 stance an increase of ash on dialysis was found to obtain 4 . For our own 

 part we found that dialysis of a solution of scale carrageen extending 

 over a period of nearly a month in running water reduced the ash from 

 22-79 per cent, to but 20-55 per cent. i 



That this reluctance to dialyse was not due to any peculiar attraction 

 of the colloidal material for salts was shown by the fact that a solution 

 of scale carrageen could be entirely freed from added sodium chloride 

 or sulphate by two days' dialysis. 



Initial treatment of the solution with dilute hydrochloric acid in the 



1 Fliickiger and Hanbury, Pharmacographia, London, 1874. 



2 Czapek, Biochemie d. Pflanzen, n, 818. 



3 Fliickiger and Obermaier, Schwerz. Wochens. Pharm. 1868, xiu. 



4 Moeller and Thorns, Real Enzyklopadie d. gesammten Pharmazie, 1900, in, 382. 



