36 BOARD OF AGRICULTUEE. [Jan. 



and are carried about, as I have said, by the wind, by very 

 light currents of air, because they are so very small and 

 light ; and finally, if they fall where there is considerable 

 moisture, which is usually needed, they propagate the dis- 

 ease in a new place. It is probable that they do not, as a 

 rule, germinate very rapidly, — probably not until some of 

 the warmth of spring comes, although they can stand a 

 pretty cold temperature. 



In these two ways — by the quick germinating and super- 

 ficially produced summer spores, and by the internally pro- 

 duced and more slowly germinating winter spores — the 

 fungus is propagated and spread. The only remedy that 

 we know now is that which has been mentioned, — of cutting. 

 It is a shame that such a pesky little thing as the black- 

 knot fungus should get the upper hand of us as it has done. 

 It should call for less heroic treatment. 



Of course this whole subject of plant diseases and vege- 

 table pathology is a new one. It is a field which has not 

 been very much worked. The economic, practical side of it 

 is one which has been very little worked, because there have 

 not been many people who have had an opportunity to do 

 it. Many of the experiment stations are offering to some of 

 us who are fond of that kind of work, and want to do it, 

 opportunities to do it ; and we are going to do our best to 

 turn out results. Of course work of this kind is extremely 

 slow. There are hardly more than a dozen men in the 

 country who are engaged in that kind of work, and of course 

 that number of men will not make rapid progress ; but we 

 hope to make steady gains, take up one thing after another, 

 and get something more out of it than we know now. In 

 this black-knot question there is work for one man for half 

 a life-time, almost. 



Dr. Fisher. I would like to make one suggestion aris- 

 ing out of the remarks of Professor Humphrey. Cut out 

 the black-knot before you see the l)loom in the summer, and 

 in the winter cut out the black-knot before Februn-y. 



Adjourned to quarter past one. 



