48 TRANSACTIONS OF THE ILLINOIS 



the tree or vine, they would naturally ascend only with the current, through the solid 

 fibres, and feeding in their passage only on the decomposed sap, neither their progress 

 nor their destruction would be apparent from without, till they come to reach the softer 

 parts or shoots or the fruits above, which they have power to rob of their sap, or dis- 

 organize and appropriate to themselves. There the destructive fruit first becomes appar- 

 ent ; and in the case of the pear tree, it soon begins to creep along down the soft interior 

 bark of the limb toward the original nidus, till the whole of the soft bark of the limb is 

 involved, and all soon perishes together ; while the grape fungi seems to have power to 

 disorganize no part but the berry, and probably the liquid sap, indeed it may well he 

 questioned whether these fungi have the power to disorganize even the fruit and those 

 softer parts of the tree when they are in the highest sense, in a strictly healthy condi-, 

 tion ; that is, when not unnaturallj^ or preternaturely engorged with sap tending to be- 

 come stagnant or putrid from excessive alternations of moisture and heat. At all events 

 it is only in seasons attended with such conditions that they seem to make much pro- 

 gress. Indeed the cells of these softer parts may he destroyed simply by the corruption 

 and deprivations of their sap, while the more solid parts are evidently able for a longer 

 time to resist and survive all such losses. It is self-evident that a pear tree that has been 

 once attacked has an abundant nidus about it and within it for any number of future at- 

 tacks, unless the rotten nidus can be made uncongenial to the spores by saturating it 

 with copperas water, or kereosine or alkalies, without destroying the tree. It also is ap- 

 parent how easily these spores can be transferred from tree to tree by a careless use of 

 the same knife or saw without careful wiping. Whether these spores drift about in 

 the air as much as is sometimes imagined, I have my doubts, though they probably do to 

 some extent, like other light substances. But I am satisfied that they are germinated in 

 all needful abundance quite near at hand, in every unsound tree or vine, year after year, 

 whether they show their destructive power or not. 



I have thus given to the Society my personal impressions at the present moment ; 

 should they prove in future totally unfounded I should be disappointed, but not sorry • 

 for surely this is not a very hopeful view of our unsound or diseased vines and trees- 

 True we can layer our unsound grape vines and get sound ones, provided we cut them 

 off from their old roots. But what can we do with our unsound pear trees ? If these 

 suggestions in any manner incite to future observations and useful discovery I shall 

 heartily rejoice, and shall have achieved the main end I had in view in writing this paper. 



Respectfully submitted. 



Mr Freeman stated that lie had heard Dr. Hilgard, of St. Louis, 

 before the Ametican Association of Science, at Chicago, last August, 

 lecture upon cryptogamous plants. Prof. Hilgard said that the 

 spores of the peach rot, &c, float in the air, live in the ground, and 

 thrive under conditions of warmth and moisture. Frost will not 

 kill them. They attach themselves to and feed upon gum and albu- 

 men specially ; if a limb is bruised or a peach skin broken the spores 

 attach themselves. 



Mr. Hilgard gave figures of different fungi in various stages of 



