362 On Carrageen. Chondrus crispus 



Ptyalin. Undiluted filtered saliva and diluted saliva, obtained by 

 washing out the mouth with distilled water, gave positive results when 

 incubated at 50° C. for several hours, especially when the medium was 

 strongly alkaline. At body temperature the results after 12 hours were 

 either negative or very feebly positive. 



Extract of pancreas. Negative results both at 37° C. and 50° C. 



Hydrochloric acid. A 0-2 per cent, solution of hydrochloric acid was 

 employed so as to have an acidity approximating to that of the gastric 

 juice. A slight positive result was obtained after three hours' incubation 

 at 37° C. In the same period a much stronger reaction obtained after 

 incubation at 50° C. 



Citric acid. A 5 per cent, solution acting for two hours at 37° C. 

 gave a similar result to that obtained with 0-2 per cent, hydrochloric 

 acid at 50° C. Heated on a boiling water bath for a few minutes with 

 5 per cent, citric acid carrageen loses its gelatinising power, and the 

 solution acquires a strong reducing action to Fehling solution. The 

 difficulty experienced in making shapes of carrageen flavoured with 

 lemon juice is thus accounted for by the hydrolytic action of the acid. 



The above observations suggest that the carbohydrate portion of 

 carrageen is likely to be but slightly affected by the digestive juices of 

 the human body 1 and that the value of carrageen as a food resides in 

 its physical rather than in its chemical properties. The favourable results 

 observed after its use in invalid diet, judging from the published recipes 

 for various dishes, are due to the other ingredients — sugar, milk, eggs, 

 etc.— rather than to the carrageen which provides a pleasing vehicle: 

 moreover when it is borne in mind that the strength of the jelly is rarely 

 likely to exceed 5 per cent., the amount of carrageen consumed in such 

 dishes would be insignificant. 



In view of the modern interest in vitamines and the possibility of 

 these substances being responsible for the favourable results recorded 

 in the use of carrageen, Dr Drummond, of University College, kindly 

 undertook the investigation of the material from this point of view; 

 he reported that he was unable to find any traces of either of the fractions 

 associated with vitamines. 



1 The fact that cattle are capable of digesting cellulose by bacterial action in the 

 intestine makes it impossible to express any views as to the digestibility of carrageen by 

 cattle without special experiments. 



