Fungous Disi;asls oi- Plants, Pijach Viillows 159 



or Dr. Pcnhallow his fiii.;! authorities on the matter of soil ex- 

 haustion or infertility, altlioui;h he spent mutii time stU(Jyinj[T their 

 conclusions and information sources. In the AniiUiil Report of the 

 Scitc/jry of the' Michigiin Stiite Po/fw/ogical Society for 1871, he 

 found that Dr. Kedzie and Dr. lieal had made and published some 

 chemical and microscopical examinations of peach yellows. Work 

 also had been done at the Connecticut Agricultural Experiment 

 Station. He went among orchardists and nurserymen and discussed 

 such questions as to what influence, if any, excessive use of nitro- 

 genous manure had on producing or spreading the infection, what 

 degeneration of sfock could be attributed to continued propagation 

 by budding, and again and again he verified his belief that yellows 

 attacked seedling trees no less than budded ones even as it attacked 

 recently originated varieties and the older or oldest tree stock. 

 The disease attacked trees grown on land nearly exhaused by 

 cropping, and it was known to appear on trees grown on virgin 

 soil, that is, land cleared of its original forest within less than 

 a decade. 



Smith admitted some validity to the claim that the disease was 

 propagated from imperfect or infected pits, but little exact knowl- 

 edge on this point was available because of a dearth of carefully 

 planned experiments. Arthur's experiment at Geneva, New York, 

 and those of Michigan nurserymen about whom Garfield had 

 written, and experiments in Pennsylvania and Maryland, had 

 yielded inconclusive results. So Smith had arranged with Bailey, 

 Troop, Taft, and other trustworthy horticulturists, to grow, under 

 controlled conditions, hundreds of budded and healthy trees to 

 study the origin and communicability of the infection, if found 

 contagious. Care, of course, was required to preclude the possi- 

 bility of introducing the disease in orchard areas not yet affected. 

 Smith, at his father's place at Hubbardston, Michigan, set out 

 several hundred trees. The experiments again proved inconclusive, 

 but years were required to settle the many points under investi- 

 gation. Bailey secured a field north of the Agricultural College 

 grounds and, with the help of C. S. Crandall, set out an experi- 

 mental orchard. He in 1888 offered Smith laboratory facilities 

 for his work with the microscope. Smith, aware that much further 

 field and laboratory research was necessary, advanced few definite 

 theories this year. But on this point he seemed rather sure: 



