232 BOARD OF AGPJCULTURE. 



grower ; and, as far as can be learned, on this point opinions 

 differ. 



My object in describing, in what you may perhaps consider 

 too great detail, the two principal blights on American grapes, 

 has been to show that an accurate and scientific knowledn-e 

 of the causes of disease in plants requires a careful micro- 

 scopic study, and that such study is not without definite and 

 even practical results. The time has passed when the labors 

 of botanists should be considered of interest only to special 

 students of science. From them the farmer may learn cer- 

 tain facts of which he cannot afford to be ignorant. The 

 high science of one decade, it must be remembered, becomes, 

 in the course of three or four decades, the popular belief, and 

 is then honored with the name of common sense, just as 

 though, not more than half a century previously, people had 

 not been considered fools for believing just such things. 

 Only within a few years have fungi been recognized as the 

 cause of disease in plants ; and there is a growing tendency 

 to account for almost all obscure plant-diseases by saying that ' 

 they are caused by fungi. If a disease suddenly makes its 

 appearance, and inquiry is made as to its cause, up jumps Dr. 

 A., and says, " It is a fungus : I have found some mycelium." 

 Or Professor B. startles the community with the announce- 

 ment that he has found " spores." Neither Dr. A. nor Pro- 

 fessor B. tells the public to what form the mycelium and 

 spores belong ; nor do they apparently know that it is almost 

 impossible to find a leaf or stem in which, or on which, there 

 are not some traces of mycelium or spores. The spores and 

 mycelia of the common moulds are everywhere ; and, if one is 

 determined to see in fungi the cause of all diseases, he has not 

 to look long before finding them in abundance, — such as they 

 are. It savors decidedly of quackery to make a little bit of 

 mycelium, or a few spores of some ordinary mould, explain 

 the appearance of wide-spread and devastating diseases. A 

 few years ago every thing was laid to insects by the agricultu- 

 ral quacks ; but, as a knowledge of entomology spread, that 

 became dangerous ground, and they then took up fungi, about 

 which the public were not so well informed. Before long, 

 it is to be hoped, there will be such a general knowledge of 

 the habits of fungi, that the war-cry, " Mycelium ! Spores ! " 

 will have lost its terrors. Where, then, will the quacks take 



