no 



PROCEEDINGS OP SECTION B. 



The fresh juice tested in the usual manner gave only the slightest 

 tint to the wool. 



Twenty-five grams of the residue were covered with 100 c.c, of 

 water containing 5 per cent, of acetic acid, and allowed to stand for 

 sixtesn days. The solution was then poured ofE and tested as usual. 

 It gave a brown stain to the final wool, but the stain was not quite as 

 deep as that from sample No. 1. 



Five per cent, acetic acid will therefore extract the colouring matter 

 from the residue. 



It appears, therefore, that the cause of the brown stain may be 

 due either to decomposition of the raspberry juice, or to the contact 

 of the juice with some of the solid matter of the raspberries. 



The colouring matter from the Japanese red plum was also tested 

 in the same way. No fresh plums being available at the time, plum 

 jam made from Japanese plums and sugar only was used as the source 

 of the colouring matter. 



Sixty-three grams of the jam were heated with a little water, 

 filtered and washed with boiling water until the filtrate amounted to 

 50 c.c. On testing this solution in the usual way the final wool was 

 stained brown. It appears, therefore, that the colouring matter in 

 raspberries is not the only vegetable colouring matter which will give 

 a brown stain to the final wool. 



The Action of various Reagents on Raspberry Juice. — E. Spaeth 

 (Zeit. fur Untersuch. der Nahr. und Genussmittel, 1899, ii., 633-635 ; 

 Abst. Analyst Vol. 25 (1900), p. 10) gives a list of the action of 

 various reagents upon a number of colouring matters, one of which 

 is that of raspberries, and the efiect of some of these reagents upon the 

 above samples was tried, but the results did not agree with those of 

 Spaeth, and did not agree with one another. A comparative table is 

 given below : — • 



