REPORTS OF AUXILIARY SOCIETIES. 2G9 



to secure a uniformly dry atmosphere, there need be no troul)le from dry rot ; 

 but as these conditions often cannot be perfectly met, various processes have 

 been devised for the preservation of timber. Coal tar, corrosive sublimate, 

 sulphate of copper, sulphate of iron and numerous other preparations have 

 been employed with variable success. A late writer concludes a treatise on this 

 subject as follows : "In conclusion, we can only summarize our remarks on 

 the cause of dry rot by saying, season and ventilate, in every case; as to the 

 cure that is not so easy to deal with ;" another fact going to show that diseased 

 trees and diseased timber have much in common with diseased humanity, in 

 ■whose case prevention is of most importance since " the cure is not so easy to 

 deal with." 



BACTERIA. 



There remains for our study a single class of vegetable organisms, the Bac- 

 teria, that within a few years have become famous for their now demonstrated 

 connection with fermentation, putrifaction, and disease. Some of the best 

 known of these " lowest forms of life ■' are certain s])ecies that uniformly 

 accompany, and are believed to be the active cause of splenic fever, fowl 

 cholera, and certain other diseases. By the experiments of Pasteur, Koch, and 

 a few other investigators, the real nature of these deadly germs and their con- 

 nection with the diseases mentioned have been clearly pointed out, and the 

 nature and control of contagious diseases in man and the higher animals are 

 becoming more and more a matter of exact scientific knowledge. Very 

 recently the attention of vegetable physiologists has been directed to organisms 

 of apparently the same nature that occur in great numbers in the tissues of 

 blighted pear trees and in other diseased plants. Prof. T. J. Burrill, of Illinois, 

 reports the presence of these organisms, not only in pear trees affected with 

 blight, but also in various other trees similarly diseased. These later investi- 

 gations have been carried on so recently that it is impossible, as yet, to know 

 just how much significance >to attach to them, and there is need of their con- 

 firmation on the part of competent observers. Should the announced discov- 

 ery be confirmed, it will throw much light on some of the most insidious and 

 fatal diseases to which our cultivated fruit trees are subject. Meantime, in 

 view of the striking results that have been attained in the old world through 

 the experimental study of disease germs, it will hardly be thought fanciful to 

 say that in the same line great possibilities are suggested in relation to the 

 protection of fruit trees against diseases of similar origin. If a chicken can be 

 protected against fowl cholera by vaccination, why may not a pear tree be 

 secured against blight, and a peach tree against the yellows by the same 

 means ? 



