Mr. Knight on the 
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the apple and crab tree, the woods of which were distinguish- 
able from each other by their colours, I took off, early in the 
spring, portions of bark of equal length, from branches of 
equal size, and I transposed these pieces of bark, inclosing a 
part of the stem of the apple tree with a covering of the bark 
of the crab tree, which extended quite round it, and applying 
the bark of the apple tree to the stem of the crab tree in the 
same manner. Bandages were then applied to keep the trans- 
posed bark and the alburnum in contact with each other ; and 
the air was excluded by a plaister composed of bees-wax and 
turpentine, and with a covering of tempered clay. 
The interior surface of the bark of the crab tree presented 
numerous sinuosities, which corresponded with similar inequali- 
ties on the surface of the alburnum, occasioned by the former 
existence of many lateral branches. The interior surface of 
the bark of the apple tree, as well as the external surface of 
the alburnum, was, on the contrary, perfectly smooth and 
even. A vital union soon took place between the transposed 
pieces of bark, and the alburnum and bark of the trees to 
which they were applied ; and in the autumn it appeared evi- 
dent, that a layer of alburnum had been, in every instance, 
formed beneath the transposed pieces of bark,, which were 
then taken off. 
Examining the organization of the alburnum, which had 
been generated beneath the transposed pieces of bark of the 
crab tree, and which had formed a perfect union with the al- 
burnum of the apple tree, I could not discover any traces of 
the sinuosities I had noticed ; nor was the uneven surface of 
the alburnum of the crab tree more changed by the smooth 
transposed bark of the apple tree. The newly generated 
