1891-92-] Vegetable Fibres used in BrusJimaking. 17 



summer on the growth of the leaves of some garden flowers. 

 In Henfrey's ' Elements of Botany ' I find two kinds of growth 

 of leaves described, which he calls basipetal and basifugal. 

 He says (p. 599, third edition) — 



As a rule, the first part of the leaf formed is its point, which is grad- 

 ually pushed out by development at the point of junction of leaf and stem. 

 The apical growth of the leaf is generally soon arrested. . . . The pushing- 

 out of the leaf by development at its base may be well observed in the 

 leaves of Hyacinth-bulbs developed in early spring. . . . The basilar or 

 basipetal mode of leaf- formation above described is that which is most 

 frequent ; but in some instances the apex of the leaf, instead of early 

 losing its power of growth, continues to grow and develop new cells in that 

 situation, the cells at the base of the leaf, in these cases, being the oldest. 

 This mode of leaf- formation is called basifugal. 



In several leaves which I have observed, a third kind of 

 growth takes place, which is quite different from either of 

 these, notably in the garden nasturtium (Tropaeolurn). By 

 comparing the young leaves with the oldest that can be got 

 at the end of summer, which are several times larger in linear 

 magnitude, I find that the venation of all the leaves is exactly 

 the same, and I infer that the growth has taken place by the 

 stretching of each particle of the leaf. The process may be 

 compared to that which would take place if we took a square 

 inch of thin indiarubber, and stretched it to double its length 

 and double its breadth. It is very marked in the so-called 

 horse-shoe geraniums. I believe a similar process takes place 

 in a great number of leaves, among which I will only instance 

 that of the Butterburr (Pctasitcs vulgaris). 



III.— VEGETABLE FIBRES USED IN BRUSH- 

 MAKING. 



By Mr THOMAS WEIGHT. 

 {Read Dec. 23, 1891.) 



The staple article used in the brush trade is bristles — i.e., 

 hairs of the wild boar. Bussia is the chief source of supply, 

 but it is also gathered in America, China, Turkey, Greece, and 

 nearer home in the forests of Germany and France. Horse- 



VOL. III. B 



