FRUCTOSANS 173 



lichenase should occur in the snail is significant in view of the 

 wide distribution of lichenin in the plant world. 



PARA-DEXTRANE AND PARA-ISODEXTRANE. 



These substances have been isolated from Boletus ediilis 

 and Polyporus hetulinus respectively. The former gives a 

 yellow colour with chlorzinc iodide, and the latter a blue when 

 treated with iodine and sulphuric acid. Both give glucose on 

 hydrolysis. 



FRUCTOSANS. 



INULIN. 



This substance is commonly found as a reserve food-stuff, 

 of the same nature as starch, existing in a state of solution in 

 the cell sap of a number of plants belonging to the natural 

 order Compositge, e.g. in the tubers of the dahlia and artichoke 

 [Helianthus tuberosus), and in the fleshy roots of the chicory 

 [Cichorium Intihus). It has also been described as occurring in 

 the following natural orders : Violaceas, Malpighiacege, Drose- 

 raceae, Candolleaceae, Goodeniaceae, Campanulaceae, Lobelia- 

 ceae, Myoporineae, Liliaceae, and Amaryllidaceae ; also in some 

 Algae, e.g. Neomeris. 



Inulin, or closely allied substances, are not infrequently 

 found in company with starch, especially in some Monocoty- 

 ledons, and exhibits the same peculiarity in its occurrence, 

 as has already been remarked upon in connection with starch 

 in monocotyledonous plants (p. 148). 



Thus in Iris pseudacoriis starch is present but not abundant, 

 in Iris Xiphium both starch and inulin are present in quan- 

 tity ; Scilla nutans has inulin but no starch, while Scilla 

 sibirica, and also Hyacinthus and Muscari botryoides have both 

 starch and inulin. 



According to Grafe and Vouk * and Melchior,t inulin is 

 found in the leaves of Cichorium intibus and Marcgravia spp., 

 and is considered to be a direct assimilatory product. On the 

 other hand, Colin J finds that the leaves of Helianthus tuberosus 



* Grafe and Vouk : " Biochem. Zeit.," 1912, 43, 424 ; 1913, 56, 249. 

 t Melchior : " Ber. deut. bot. Gesells.," 1924. 42, 198. 

 I Colin : " Compt. rend.," 1918, 166, 224, 305 ; " Bull. Assoc. Chim. 

 Sue," 1919. 37> 121 ; " Bull. Soc. chim. biol.," 1925, 7, 173. 



