.42 THE FLORIST AND 
wood on the outside. I supposed, and, I think, without any great phylo- 
logical research, any one would come to the same conclusion, that two years 
previously the frost or winter had been sufficient to kill the wood, but not 
the bark, or, perhaps, portions of the wood contiguous to the bark, and that 
through this channel just enough sap had been drawn barely to support 
existence, and send down two weak courses of wood. I do not know that 
it has ever been noticed by any writer, that the bark of plants posesses 
sometimes a greater power of resistance to the effects of frost than their 
wood, nor, indeed, had I ever met with any circumstance that suggested 
such an idea to me before ; but I think that conclusion in this case was 
irresistible. With respect to the short supply of sap, such a state of things 
induced, being the cause of the yellowness of the leaves, there was no room 
to doubt ; because it has become an admitted principle in physiology that 
the yellowness that precedes the fall of the leaf is in consequence of the 
failure of the tree to supply moisture to its leaves, as in the Linden during 
the comparative drought of Autumn ; or the inability of the tree to prevent 
the settlement of earthy matter in their pores, by cold weather rendering 
the circulation sluggish, as in the Hickory after the first white frost. 
In the case of a Peach tree under the " yellows," repeated examinations 
of the wood since the above observations were made, convince me that the 
Peach also is a plant which will carry its bark safely through a winter severe 
enough to destroy the wood which it encloses ; and that the same reduced 
supply of sap produces the same identical "yellows" as in the Evonymus. 
I think, moreover, that the apparently differing views of the many writers 
on the subject, all lead to this view of the real nature of the disease. The 
northern aspect, I have before noticed, prevents that freezing and thawing 
which makes frost so very destructive to vegetation. In the last report of 
the Pomological Congress, Mr. S. Feast, of Baltimore, remarks that " bad 
soil is undoubtedly the cause of the yellows ;" and if in bad soil the yellows 
are common, it is easily accounted for by the fact that cold, clayey soil, a 
bad soil for the Peach, favors the production of watery wood, just the kind 
of wood for frosts to operate injuriously upon. That the soil 'per se is not 
the cause, is apparent from the fact noticed by other writers, who tell us 
that the " yellows" are unknown in England, where we may reasonably sup- 
pose they sometimes get into bad soil, as well as here. These latter writers 
rather attribute the disease to the "luxurious growths" the Peach makes in 
this country, compared with its growths European ; but, as the Osage 
orange, mulberries, and many other trees, grow with such comparatively 
increased "luxuriousness," this alone, neither can be a cause, while it still 
