12 



may be seen best on specimens in the laboratory. A common fruit 

 jar, in wliich is placed a four or six inch piece of an infected limb, 

 will, in thirty-six or forty-eight hours show signs of the fruiting 

 bodies. First put the stick into water for two or three minutes then 

 transfer it to the jar in which there is less than half an inch of 

 water. The jar is closed and kept at summer temperature. A warm 

 cellar is most convenient, since the fungus grows in the dark as 

 well as it does in the light. In this way the writer has had an 

 abundant supply during the past winter of fruiting pustules on 

 limbs of the native chestnut, Castanea dentata; on the Japanese chest- 

 nut, Castanea crenata; and on the Paragon, which is probably a 

 variety of the Spanish or sweet chestnut, Castanea vesca. From these 

 specimens the two kinds of spores were at hand during the entire 

 winter. 



I^»reign chestnut trees sometimes attain an immense size, and are 

 quite common in the south of Europe, in Spain, Italy, Switzerland, 

 and Germany. The fruit or nut which is two or three times the 

 size tlie American nut is much used as an article of food. The large 

 kernel is frequently ground into meal and is used to thicken soups, 

 and even bread is made of the chestnut flour. The largest foreign 

 chestnut tree is on the slope of Mt. Etna, in Sicil}^ and has a cir- 

 cumference of IDO feet, nnd is known as the ''Castagno di cento 

 cavalli," the cliestnut of one hundred horses. 



There is no lack of op])oi-tunity for spores to find an entrance be- 

 neath the bark of a chestnut tree, large or small. The wood is brit- 

 tle and tlie stonus of winter leave many broken twigs and limbs. The 

 small boys and older nut gatherers have clubbed the trees and left 

 many a scar. Insect borers and woodpeckers have made openings in 

 the bark in many places. The forks of the branches seem to be 

 favorite places for the lodgment of spores. In a young tree ten or 

 more points of infection Iiave been observed at the break of the bark 

 in tlie forks of the limbs. 



The yirojiagalion is readily carried on wherever there is a supply 

 of s})()res. The transportation and ready access to the cambium wood 

 cells ai-e well provided. On Long Island an isolated tree, more than 

 a mile distant from any chestnut growth was infected. 



IMMUNITY OF OTHER TREES. 



All the other forest trees seem to be inmiune. There are fungus 

 growths of the sa])rophytic type on all forest trees. Abundant si)ores 

 of another s])ecies of fungus were found upon the branches of several 

 oak trees. The trouble was limited to the under side of the branches, 

 and there was no tendency on the part of the fungus to invade the 

 new cells of the cambium or to girdle the branch. An examination of 



