42 TRANSACTIONS OF THE ILLINOIS 



from 1848 to 1852, as the Black Rot and the Brown Rot. I have seen no reason to 

 change the terms of those descriptions since, though many slighter forms of pear-tree 

 blight caused by various insects might be added to the general list. What is called 

 the Grape rot in Europe, seems to be merely one form of our common mildew, and is 

 entirely distinct from both of our fatal forms of Western grape-rot above named. 

 The little pale watery spot on the grape being the first symptom of the Brown grape- 

 rot, and a dry bla-ck spot, of the Black rot. 



The fatal pear tree blight generally begins with a dead blotch on the outer bark of 

 the trunk or lower limbs, months before it appears on the dead leaves and shoots 

 above ; and if this dead patch of bark is seasonably removed with a sharp knife, and 

 the parts washed with spirits of Turpentine and Lamp black early in the Spring, before 

 it communicates the poison (or whatever it is) to the sap, the blight in the top will 

 not usually ensue, and the tree will be saved. These dead spots on the bark usually 

 appear in an oblong shape from one- half inch to several inches in diameter. Those 

 generally near to the forks of the tree, or at some point where the young tree is chang- 

 ing from a smooth to a rough bark tree, thus intimating that the compressure by 

 stricture of parts, of the downward flow of the sap, is one item in the cause of the 

 malady ; and high feeding in spring with animal manures, combined with plenti- 

 ful rains to increase the volume of the return sap through those strictured passes, un- 

 doubtedly increases the danger. With us, pear trees are seldom affected with this 

 blight till near the age of bearing, or after some part of the trunk begins to change 

 from smooth to rough bark. Nor does the grape-rot usually affect quite young vines, 

 in either of the above specified forms ; which forms seem after all to be sometimes 

 interchangeable and probably of the same general origin. 



In these earlier papers, I was inclined to enquire at first for an insect origin of one or 

 both of these forms of blight, as will be seen from their perusal ; but before I closed 

 my investigations at that time, I became as I then intimated, inclined to the opinion 

 that these diseases were the result of fungi, though beyond all question, there are 

 various microscopic and other forms of insects that cause the tips and leaves of pear 

 trees to blight, and the grapes to rot on the vines ; yet these results are totally distinct 

 from that deadly " Upas " of the pear tree known, " par excellence " as the Pear Tree 

 Blight, and that terrible and sudden destruction of the whole crop known as the Grape 

 rot in the West ; and so far as I can as yet learn, totally unknown in Europe. 



A year or two after this time, about 1851, under the lens of a powerful solar micro- 

 scope, at the Farmer's College near Cincinnati, Ohio, I examined grapes in various 

 stages of blighting, which fully convinced me that in the case of the grapes, the dis- 

 ease was wholly of fungoid, or cryptogamous origin. The filaments or threads or 

 roots of these fungoid growths could be plainly seen interlacing the little cells of the 

 fruit, and apparently progressing in their growth from the stem of the berry of the 

 grape toward the blighted spot on the surface ; thus at that time suggesting the idea 

 to me that the spores or little seeds that started the plant or fungi, came into the berry 

 through the stem with the sap, and not by falling or lighting on the skin or outer sur- 

 face of the berry. Several years after that time in 1863, Dr. Salisbury published his mon- 

 ogram with' drawings of various fungi, affecting the Pear, Quince, Apple and Peach trees 

 and their fruit, in the Ohio State Agr'l Transactions, which appears almost identically 

 the same with those I saw in the Grape in the same state of Ohio, some ten years before. 

 These and other similar facts have greatly confirmed my original suspicions, and set me 

 to looking for the probable winter quarters, or nidus of the spores of these fungi, dur- 



