10 POTATO DISEASE. 



J. G. W. of Utica, in the " Country Gentleman," of Feb. 19, 

 attacks the fungus theory with great spirit and vigor. He exerts 

 considerable rhetoric against those who deal with nature under "bell- 

 glasses," makes fun of trying an exjjerimenium crucis on a piece 

 of dead and cut potato, and throughout so travesties the fungus 

 theory, or rather the plain statements on which it is based, that 

 they are absurd to anybody. But J. G. W. offers no facts to rebut 

 this theory. He does not tell us of a single observation which dis- 

 proves the statement that the fungus always precedes the leaf- 

 blight and the tuber-rot, and that the leaf-blight and tuber-rot 

 always/oZ/oio the fungus. He does not stop to reflect that this 

 statement is the result of oft-repeated observations made during 

 six years by Speerschnieder, De Bary and Kuhn, all skillful phys- 

 iologists. He offers no evidence that an experwientum crucis can- 

 not be made elsewhere than under the open sky. Through half 

 his article, while he ridicules effectively, he does not reason at all, 

 and when at last he begins with logic, it were better had he kept 

 to rhetoric, 



" As if the world did not know," he says, " what evidently the 

 German did not know, that if two rows of potatoes planted side by 

 side — nay of two potatoes planted in the same hill, one of a deli- 

 cate and the other of a hardy variety, a Blue Mercer and a Garnet 

 Chili for example, the one shall be perfectly sound and the other 

 perfectly rotten." This may be a stubborn fact for the fungus theo- 

 rizers. But it is not more inexplicable than some others known, 

 very likely to the aforesaid German. I have seen, of two rows of 

 potatoes planted side by side — nay of two potatoes planted in the 

 same hill — one perfectly sound, and the other perfectly rotten, and 

 both of the same variety! It is not uncommon that a streak or 

 well-defined patch in a field is diseased, while the remainder is 

 what would be called by most out-of-door philosophers, perfectly 

 healthy. 



It is very common to dig from the same hill, sound and rotten 

 tubers, and I have dug from a hill an upper stratum of rotten pota- 

 toes, and a lower one of sound ones. I can't conclude, as J. G. 

 W. does, that "in these cases the sound potatoes stood the same 

 chance of meeting the fungus spores in their descent as the decayed 

 ones." If an angler by throwing his hook into the stream, catches 

 a shiner, it does not necessarily follow that every time he throws it 

 in he will take a fish, much less that he will depopulate the brook. 



