PEACH YELLOWa. 243 



CJarolina, and probably in Georgia as well, though perhaps there is, in the 

 latter, some variation from its characteristics in the north, except as to fatal- 

 ity. Mr. Smith thus states his 



CONCLUSIONS. 



The literature of peach yellows is a medley of contradictions. All sorts of 

 views have been promulgated, with greater or less show of wisdom, and many 

 theories have been built on a very slender basis. It would seem that at least 

 a personal acquaintance with the disease ought to be requisite to writing on 

 such a perplexing subject, yet even this does not appear to have been thought 

 necessary in all cases, those who knew the least having often expressed their 

 opinions with the most confidence. In connection with my field studies, I 

 have endeavored to find, read, and sift the whole of this voluminous and incon- 

 gruous mass of writing, and in the preceding pages I have presented all that 

 seems pertinent to the question of history and distribution. Wherever pos- 

 sible, the writers have been allowed to tell their story in their own way, only 

 such portions being suppressed as seemed foolish, irrelevant, contradictory, or 

 untrustworthy. Two reasons led me to quote rather than summarize and 

 speak ex cathedra: (1) The inaccessibility of a very considerable portion of 

 the early literature, some of which has been misquoted frequently. (2) A 

 feeling, shared in common, I doubt not, with many others, that statements 

 are more certainly to be depended upon when safely inclosed between quotation 

 marks than when condensed or paraphrased. 



Among the facts which I believe to be well established by this inquiry are: 



(1) That yellows has frequently b3en confounded with other diseases of the 

 peach, especially in New Jersey, where the borer and the root aphis are very 

 prevalent. 



(2) That genuine peach yellows appeared in the vicinity of Philadelphia 

 prior to 1791. 



(3) That since 1791 the country has never been entirely free from this 

 disease. 



(4) That it was prevalent on the Atlantic coast long before it appeared in 

 the west. 



(5) That the area of its action has extended northeast, north, and north- 

 west much more rapidly than south. 



(6) That it is now more or less prevalent from Massachusetts to Georgia 

 and westward to Lake Michigan and the Mississippi. 



(7) That the disease spreads from centers, usually appearing first in locali- 

 'ties thickly set with orchards. 



(8) That the first cases of yellows in any district are usually, if not always, 

 in young trees imported from infected localities. 



(9) That everywhere it is the same destructive malady. 



Some deductions which may be accepted provisionally and with more or 

 less caution are : 



(1) The disease is confined to the United States. 



(2) It is absent from the Gulf States and from those west of the Missis- 

 sippi. 



(3) There have been great outbreaks of the disease, e. g., 1791, 1806-'07, 

 1817-21, 1845-'58, 1874-";8, 188()-'87-'88, followed, apparently, by periods 

 of comparative immunity. 



