Lvii. on Carrageen (chondrus Crispus). Iii. the Constitution of the Cell Wall1

HISTORICAL. MANY workers have from time to time investigated Chondrus crispus, but of recent years the most exhaustive work has been done by Sebor. The presence of galactose had been established by Fluckiger and Obermayer [1868], and Bente [1875, 1876] had found among the products of the action ,f acid upon carrageen levulinic acid and a sugar, which showed little or no optical activity. Haedicke, Bauer and Tollens [1867] established in carrageen mucilage the presence of fructose and calculated that it contained 28 % of galactose. They suggested that these sugars might be present under the form of raffinose. Sebor [1900] determined to identify the remaining sugars. He confirmed the presence of galactose and fructose, found small quantities of pentosan and showed that raffinose is not present. He also stated that he had found evidence of glucose. He oxidised the carrageen mucilage, but, after filtering off the mucic acid, failed to obtain any acid potassium saccharate on treating with potassium carbonate and acetic acid. As an analysis of the silver salt gives the same result for both mucate and saccharate he tested the potassium solution for optical activity, but found it inactive, whereas the saccharate should be active. He therefore abandoned the oxidation products and tested for glucose in a hydrolysed solution of mucilage. He hydrolysed with 6N HCI to destroy the fructose, and when the solution no longer gave a Selivanoff reaction, added benzylphenylhydrazine. He separated off the benzylphenylhydrazone of galactose and found the remaining compound had a melting point of 1630, that of glucose benzylphenylhydrazone being 1650. He declared that the hydrazone was a mixture and his paper gives the impression that he was not satisfied with the agreement of melting points referred to above. This appears to be all the evidence he had in favour of the presence of glucose among the constituents of carrageen. Miither and Tollens [1904] state that glucose is among the constituents of carrageen, but all the evidence they offer is an estimation of the amount of silver present in the silver salt of an oxidation. product; this is obviously useless since the amount of silver is the same in the salts of both saccharic and mucic acids. Abderhalden's Biochemisches Handlexikon [1911] contains the statement that the pure mucilage of carrageen corresponds to the formula C6H1005, but