36 TRANSACTIONS OF THE ILLINOIS 



* * * But further discovery is due also to the microscope, that the property of loco- 

 motion belongs universally to the germ spores and antheridia of all cryptogamic plants. 

 Gray also remarks, not only moulds and blights, live in this predacious way, but many 

 flowering herbs and shrubs." And as seeing is believing, two years ago, while examin- 

 ing with the microscope, a fungus, which had attacked our Norway firs, and which 

 grew out of the pores of the leaves, we distinctly saw one of the blossom-like plants 

 open and send out a minute powder. This was doubtless the spores which only needed 

 proper resting places to fix themselves and reproduce. The disease certainly did spread 

 with great rapidity. Now we know the air is continually full of vegetable life, only 

 waiting those conditions adapted to their peculiar wants, to increase almost beyond our 

 comprehension. In view of the facts of which mention has just been made, it seems 

 impossible to conceive of a substance from which the seeds of such minute forms of 

 vegetable organisms may be excluded. Our fruits are stung, then comes moisture and 

 heat, and then also comes the blight in our trees and rot in our fruit. 



The remedy we offer for the pear tree blight, although original with us is by no means 

 a new one. We first practised it some eighteen years ago, and from that time to the 

 present, it has in no instance failed to produce the results claimed for it. It does not 

 ward off the attacks of eryptogomus i>lants as an examination of our root-pruned trees 

 will show, for they are all more or less injured between the outer and inner bark. All 

 that we claim is, that when a pear tree is so root-pruned as to force it to form the ani- 

 mal buds by the time the blight first makes its appearance, the tree can then sustain 

 no other injury from its presence than the loss of the infected portions of bark, and 

 for the reason that time enough will not have elapsed from the time the fungus becomes 

 active in the spring to the time the circulation in the trees is so arrested as to afford no 

 means for its dissemination. We have already shown as we suppose, that pear-blight 

 is due to a chemical change of the sap induced by the union of the sap or watery por- 

 tions of fungus becoming mixed with that of the pear, whereby the whole becomes so 

 changed as to destroy the alburnum whersver this substance is brought with it, but 

 when it is confined to the live portions of bark and the growth of the tree is checked 

 in time, it dries out, without penetratiug to the new woody matter in process of growth, 

 thus producing those dead patches of bark sometimes found on trees of slow growth. 

 On the other hand were the circulation very active the poison would not be arrested in 

 the bark, but would soon pass through it to other parts of the tree. 



At each of the points visited by us this season, we secured the promise of parties to 

 root-prune their pear trees infected with fire blight, so called, strictly in accordance 

 with our written instruct ions, the trenches made in pruning, to be left open until they 

 were inspected by a committee appointed by the local horticultural society, or where 

 no local society exists, the examination to be made by one or more horticulturists, who 

 with the owner of the trees shall make report as to the manner in which the work was 

 done and its effects on the trees. 



ROOT-PRUNING THE PEAR A PREVENTIVE OF BLIGHT. 



Root-pruning may be performed from November to April. The latter part of winter 

 or spring is best, as the sub-soil is then easily penetrated by a spade. For trees the 

 circumference of which is twelve (12) inches at one foot above the ground, mark a 



