TRANSACTIONS OF THE SECTIONS. 'J9 



eluded, then we find it present in many instances where neither buds, 

 leaves, or bark, can be said to exist, as in Cryptogamic plants, especially 

 various species of jBoleti. It is also found in many parts of Phanero- 

 gamous plants, as the pericarps of the cocoa, beech, and other plants 

 which in those parts are destitute of leaves. The author had also 

 found woody tissue in abundance in the leafless Monotropa, and in 

 many species of Cactacece. 



Another objection to the theory of Du Petit Thouars is found in 

 the fact of wounds of trees filling up at the lower as well as the upper 

 lip. In trees that had been felled, the author had observed the pro- 

 duction of fibrous tissue independent of leaves or buds, (specimens of 

 this were exhibited to the Section). 



The author then detailed some experiments he had made by ringing 

 beech trees in the spring of the year. When cut down in August, a 

 cellular and woody formation appeared both in the upper and lower 

 lips of the wounds, the woody tissue having been formed subsequent 

 to the ringing. 



The last occurrence to which the author directed attention, and 

 which could not be explained by this theory, was the existence 

 of knobs of wood in the bark of beech and other trees. These 

 excrescences are of all sizes, and when first formed, are cellular; 

 they gradually harden, and at last present layers of contorted woody 

 fibre. They have a regular bark of their own, filled with sap during 

 the spring, and present, when cut, concentric circles of woody 

 tissue representing their yearly growth. Many of them put forth 

 buds, and some few of them leaves, but by far the greater number have 

 neither buds nor leaves. Sometimes several are found together in a 

 mass (especially in the elm and acacia), each nucleus having a sepa- 

 rate series of concentric layers surrounding it. Although, from rapid 

 growth, the compound knobs are found in contact with the wood of 

 the tree, the single knobs are seldom found in this position. These 

 knobs have been called by Dutrochet embryo buds. The conclusions 

 which the author advanced, from his present knowledge of the facts, 

 were, 



1st. That the requisites for the formation of wood are, 1. a living 

 tissue developing elongated fibres ; 2. a tissue forming and depositing 

 secreted matter ; and 3. exposure to the influence of external stimuli. 



2nd. That the secreted matters are more easily brought under the 

 influence of external stimuli in the younger tissues ; hence the import- 

 ance of leaves. 



3rd. That neither bark nor leaves are essential to the formation of 

 woody fibre. 



Notice of Zoological Researches in Orkney and Shetland during the month 

 of June 1839. By Edward Forbes and John Goods ir, Esquires. 



During their short excursion, the authors directed their attention 

 almost exclusively to the invertebrate animals. Of mollusca, they 



