456 History of the Author's 



for a considerable time after shearing, is coarser than the average of the fleece 

 during its subsequent growth ; whence, as the wool, like the nails, grows by pro- 

 pulsion, the outer extremity is always the coarsest part. 



It is not, however, certain that this argument is not founded on a fallacy. The 

 growth of wool is not mere propulsion. There is, doubtless, in every filament, 

 some circulation of juices derived from the organized bulb from which it rises ; and, 

 for ought we know, shearing might produce a tendency to a grosser filament in 

 the hardest winter, just as cutting human hair is said to make it become stronger. 

 If the effect be the consequence of heat alone, that heat having uniformly changed 

 through successive seasons, it must follow that every filament has the form of two 

 cones, joined together by their apices, or points; and as the skin of the animal 

 must, from well-known causes, be hotter before shearing than afterwards, that part 

 of the new shorn fleece, which was next the skin, must be coarser than the wool 

 which springs immediately after shearing. These points I tru.st that I shall 

 hereafter be able to investigate by actual microscopic observation ; and, in that case, 

 shall not fail to communicate the result to the Board. 



I have hinted the possibility of some effect being produced on wool by the 

 difference of nourishment. Common opinion has gone so far as to assume that 

 fine and short grass is indispensable to the production of fine clothing wool. I have 

 already proved this to be false, with regard to the wool of the pure Merino; and 

 my finest-woolled sheep of the cross breed, in addition to fresh grass, rouan, and 

 hay, have been uniformly fed, in their respective seasons, with rape, Scots cabbage, 

 and vetches; and, occasionally, with linseed and oil-cake. It is indeed acknow- 

 ledged, that, other things being equal, the weight of the fleece will, within certain 

 limits, be proportioned to the quantity of food with which the animal is supplied. 

 1'his may be, in part, owing to some increase in the length of the filament ; but it 

 probably arises also from some increase of its diameter.* I have indeed no doubt 

 that both these effects take place, in an especial degree, where a sheep is so fattened 

 as to be fit for the butcher; in which case they are accompanied with a consider- 

 able augmentation of the weight of the fleece. On the other hand, a sheep which 

 is lean, either from want of food, or from slow disease, has the filaments of its 

 fleece shortened, and rendered finer; and I know that this effect occurs in the pure 

 Merino, as well as in its crosses. The wool, at the same time, becomes of a more 



• Whether the specific gravity of the filaments be in this case increased, I have not examined. 



