PROPERTIES OF CRYPTOGAMIC PLANTS. 49 



cabinets, moldiness may be kept away by the use of essential oil 

 or Russia leather. 



Fungi are very destructive to corn, in the form of hlight^ tnil- 

 dew, hmit, &c., doing injury not only by a diminution of the 

 quantity, but also of the nutritive matter ; and, as in the case of 

 bunt, by communicating to the corn an ofiensive taste and smell. 

 The growth of these parasites depends so much upon accidental 

 circumstances, tliat it is impossible for the most experienced cul- 

 tivators to guard against them altogether ; but the evil is greatly 

 lessened by careful choice of seed, by steeping it in solutions of 

 different substances, which destroy the vegetative power of the 

 sjporidea of these parasites, and by a judicious change of cropping 

 in the land subject to them. It appears that the reproductive 

 contents of the sporidea are absorbed, together with the water con- 

 taining the nutritive matter of the soil, by the roots. At least, it 

 is certain that corn sown in soil which has been purposely mixed 

 with the sporidea, is infested with the fungi to which those spo- 

 ridea belong ; and this has been proved also with regard to one 

 of the entophytal parasites to which roses are subject. Most 

 plants are preyed upon by their peculiar parasites ; pear-trees, for 

 instance, are sometimes much injured by yEcidium cwncellatuon, 

 and young trees planted in their neighborhood are observed to 

 suifer. 



The roots of certain plants, as Saffron-crocus^ Lucerne^ Convolv- 

 ^ilus hatatus (j^otato), are frequently exhausted by subterranean 

 fungi. In the case of saffron, the only remedy is to insulate the 

 infected spot by a deep trench ; which should seem to be a striking 

 proof that these plants are really increased by seed. M. J. Berk- 

 ley on Fungi, in " Crypt, of England." We refer the reader to 

 Kotzsch's excellent method of preserving fungi, on p. 10, vol. ii. 

 which Sir Wm. Hooker has found very serviceable. Crypt. Eng. 



According to Braconnot, most of the fungi contain a peculiar 

 principle denominated j^im^m, a peculiar acid cviWed fmigic acid 

 usually combined with potassa, and a peculiar saccharine matter 

 less sweet than the other varieties of sugar, less soluble in alcohol 

 and water than that of the cane, and distinguislied by some wri- 

 ters as the sugar of niiislirooms. Fungin constitutes the basis of 

 these vegetables, and is the principle upon which their nutritive 

 properties chiefly de^jend. It is the fleshy substance which re- 

 mains when they are treated with boiling water, holding a little 

 alkali in solution. It is whitish, soft, and insipid ; inflammable ; 



